In accordance with the terms of the Common Stock Sales Agreement, dated as of July 2, 2021, or the sales agreement, that we entered into with B. Riley Securities, Inc. (“B. Riley Securities”) and EF Hutton, division of Benchmark Investments, LLC (“EF Hutton” and together with B. Riley Securities, the “Sales Agents”), we may offer and sell shares of our common stock having an aggregate offering price of up to $10.0 million from time to time through or to the Sales Agents, acting as our agents or principals.

Our common stock currently trades on the Nasdaq Capital Market, where it is listed under the symbol “PTIX.” On June 30, 2021, the last reported sale price of our common stock was $2.88 per share.

As of June 30, 2021, the aggregate market value of our outstanding common stock held by non-affiliates, or public float, was approximately $30,678,313, based on 9,103,357 shares of outstanding Common Stock held by non-affiliates as of the date of this Prospectus, at a price of $3.37 per share, which was the last reported sale price of our common stock on the Nasdaq Capital Market on June 17, 2021. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell shares pursuant to this prospectus supplement with a value of more than one-third of the aggregate market value of our common stock held by non-affiliates in any 12-month period, so long as the aggregate market value of our common stock held by non-affiliates is less than $75,000,000. We have not offered any securities pursuant to General Instruction I.B.6 of Form S-3 during the prior 12 calendar month period that ends on and includes the date of this prospectus.

Sales of our common stock, if any, under this prospectus may be made in sales deemed to be “at the market offerings” as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, or the Securities Act. The Agents are not required to sell any specific number or dollar amount of securities, but will each act as a sales agent using commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms between the Sales Agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The compensation to the Sales Agents for sales of common stock sold pursuant to the sales agreement will be an amount equal to 3.0% of the gross proceeds of any shares of common stock sold under the sales agreement. In connection with the sale of the common stock on our behalf, the Sales Agents will be deemed to be “underwriters” within the meaning of the Securities Act and the compensation of the Sales Agents will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to the Sales Agents with respect to certain liabilities, including liabilities under the Securities Act or the Securities Exchange Act of 1934, as amended, or the Exchange Act.

Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-3 of this prospectus supplement and page 5 of the accompanying prospectus, as well as the sections captioned “Risk Factor Summary” and “Item 1A-Risk Factors” in our most recently filed annual report on Form 10-K or quarterly report on Form 10-Q which is incorporated by reference into this prospectus supplement, for certain risks you should consider. You should read all of the information set forth in this prospectus supplement, as well as the documents incorporated by reference herein, carefully before you make your investment decision.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We are offering to sell, and are seeking offers to buy, the securities only in jurisdictions where such offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the securities in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement and the accompanying prospectus must inform themselves about and observe any restrictions relating to the offering of the securities and the distribution of this prospectus supplement and the accompanying prospectus outside the United States. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying prospectus to or by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

This prospectus supplement and the accompanying prospectus are part of a registration statement that we filed with the Securities and Exchange Commission, or SEC, utilizing a shelf registration process. Under the shelf registration process, we may from time to time offer shares of our common stock having an aggregate offering price of up to $10.0 million under this prospectus supplement at prices and on terms to be determined by market conditions at the time of offering.

This prospectus supplement relates to the offering of our common stock. Before buying any of the common stock that we are offering, we urge you to carefully read this prospectus supplement and the accompanying prospectus, together with the information incorporated by reference therein, as described under the heading “Incorporation by Reference” and “Incorporation of Certain Information by Reference” in this prospectus supplement and the accompanying prospectus, respectively. These documents contain important information that you should consider when making your investment decision.

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference herein. The second part, the accompanying prospectus, provides more general information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus or any document incorporated by reference therein that was filed with the SEC prior to the date of this prospectus supplement, you should rely on the information in this prospectus supplement; provided that if any statement in one of these documents is inconsistent with a statement in another document having a later date-for example, a document incorporated by reference into this prospectus supplement or the accompanying prospectus -the statement in the document having the later date modifies or supersedes the earlier statement.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference herein were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreement, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

You should rely only on the information contained in or incorporated by reference in this prospectus and in any free writing prospectus we may authorize for use in connection with this offering. We have not and the Sales Agents have not authorized anyone to provide any information other than that contained or incorporated by reference in this prospectus or in any free writing prospectus prepared by or on behalf of us or to which we have referred you. We and the Sales Agents take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not, and is the Sales Agents are not, making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus, the documents incorporated by reference herein, and in any free writing prospectus prepared by or on behalf of us that we have authorized for use in connection with this offering is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus, the documents incorporated by reference herein, and any free writing prospectus prepared by or on behalf of us that we may authorize for use in connection with this offering, in their entirety, before making an investment decision. You should also read and consider the information in the documents we have referred you to in the sections of this prospectus supplement entitled “Where You Can Find More Information” and “Incorporation by Reference” and the sections of the accompanying prospectus entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference.”

Unless otherwise specified or required by context, references in this prospectus to “Protagenic,” “the Company,” “we,” “us” and “our” refer to Protagenic Therapeutics, Inc., a Delaware corporation and its consolidated subsidiaries, if any, unless otherwise specified.

This prospectus, including the documents that we incorporate by reference herein, contains, and any applicable prospectus supplement or free writing prospectus may contain, forward-looking statements that relate to future periods, which are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the Private Securities Litigation Reform Act of 1995, which are subject to the “safe harbor” created by those sections. The words “believe,” “may,” “estimate,” “continue,” “anticipate,” “intend,” “expect,” “predict,” “project,” “potential,” “believe,” “should,” “could” and similar expressions are intended to identify forward-looking statements. Examples of these statements include, but are not limited to, statements regarding: our future operating expenses, our future losses, the potential success of our strategy as a royalty aggregator, the extent to which our issued and pending patents may protect our products and technology, the potential of our existing product candidates to lead to the development of commercial products, and our ability to receive potential milestone or royalty payments under license and collaboration agreements and the probability, amount and timing of receipt of those payments. These and other risks, including those related to current economic and financial market conditions, are described in more detail in “Risk Factors” above and the additional risk factors contained in our most recent Annual Report on Form 10-K and Quarterly Reports on Form 10-Q. We undertake no obligation to publicly update any forward-looking statements, regardless of any new information, future events or other occurrences. We advise you, however, to consult any additional disclosures we make in our reports to the SEC on Forms 10-K, 10-Q and 8-K.

PROSPECTUS SUMMARY

This summary highlights certain information about us, this offering and selected information contained elsewhere in or incorporated by reference into this prospectus. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our common stock. For a more complete understanding of our company and this offering, you should read carefully this entire prospectus, including the information incorporated by reference into this prospectus, and any free writing prospectus that we have authorized for use in connection with this offering, including the “Risk Factors” section beginning on page S-3 of this prospectus supplement and page 5 of the accompanying prospectus and the “Risk Factor Summary” and “Risk Factors” sections of our Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, and any amendment or update thereto reflected in subsequent filings with the SEC and incorporated by reference in this prospectus, our financial statements and the related notes and the other documents incorporated by reference in this prospectus.

Company Overview

We are a biopharmaceutical corporation specializing in the discovery and development of therapeutics to treat stress-related neuropsychiatric and mood disorders utilizing synthetic forms of endogenous brain signaling peptides that can dampen overactive stress responses.

The mechanism by which we will target these stress-related disorders is based on over 15 years of work elucidating the role of Teneurin Carboxy-terminal Associated Peptide (“TCAP”), which has been found to have a central role in maintaining healthy brain signaling. TCAP is an endogenous counterbalance to the negative effects of stress and its criticality is underscored by a high degree of evolutionarily preservation. TCAP signaling counteracts the effects of Corticotropin Releasing Factor on the Hypothalamic-Pituitary-Adrenal axis, thus reducing the stress hormone cortisol. We intend to bring novel forms of TCAP into human clinical development as a treatment for stress-related neuropsychiatric disorders. Our lead compound – PT00114 – is a 41-residue peptide synthetic form of TCAP that can be administered subcutaneously, sublingually, or intra-nasally. In addition, we have a portfolio of earlier stage neuropeptides targeting the TCAP pathway that are in preclinical evaluation.

Our strategy is to develop TCAP neuropeptide-based drug candidates, beginning with PT00114, in stress-related indications, including, but not limited to: treatment resistant depression (“TRD”), which is a subgroup of major depressive disorder (“MDD”); addiction, recidivism, or substance use disorder (“SUD”); anxiety, including generalized anxiety disorder (“GAD”), and post-traumatic stress disorder (“PTSD”).

We intend to complete IND-enabling studies of PT00114 and to enter first-in-human Phase I/II studies in the third quarter of 2021. We will be initiating our clinical program with a 42-patient basket trial in collaboration with Dr. Maurizio Fava, the Psychiatrist-in-Chief of the Massachusetts General Hospital and co-principal investigator of STAR*D, the largest research study ever conducted in depression. We will enroll a healthy human cohort and four stress-related neuropsychiatric disorders: TRD, SUD, GAD, and PTSD. We will be using this study for both safety and preliminary efficacy signal-finding to prioritize indications for later stage development. we’ve chosen these four indications for multiple reasons, including direct linkage to the mechanism of TCAP in reducing biological stress signals, preclinical evidence of efficacy in animal models of these disorders, and the high unmet need in these patient populations, which creates significant market opportunity.

Corporate Information

THE OFFERING

Issuer		Protagenic Therapeutics, Inc.

Common Stock Offered By Us		Shares of our common stock having an aggregate offering price of up to $10.0 million.

Manner of Offering		“At the market offering” that may be made from time to time through or to B. Riley Securities and EF Hutton as our sales agents or principals. See “Plan of Distribution” on page S-6 of this prospectus supplement.

Use of proceeds		We currently intend to use the net proceeds from this offering primarily to acquire additional potential royalty and milestone revenue streams, for working capital and other general corporate purposes. See “Use of Proceeds” on page S-4 of this prospectus supplement.

Risk factors		Investing in our common stock involves significant risks. See “Risk Factors” beginning on page S-3 of this prospectus supplement and page 5 of the accompanying prospectus, the “Risk Factor Summary” and “Risk Factors” sections of our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q, and any amendment or update thereto reflected in subsequent filings, incorporated by reference into this prospectus supplement, and other information included and incorporated by reference in this prospectus supplement for a discussion of factors you should carefully consider before deciding to invest in our securities.

Nasdaq Capital Market Symbol		PTIX

Investing in our common stock involves a high degree of risk. Before deciding whether to invest in our common stock, you should consider carefully the risks described below and discussed in the “Risk Factor” section beginning on page 5 of the accompanying prospectus and the “Risk Factor Summary” and “Item 1A-Risk Factors” sections of our most recent Annual Report on Form 10-K and in our subsequent Quarterly Reports on Form 10-Q, and any amendment or update thereto reflected in subsequent filings with the SEC, which are incorporated by reference herein in their entirety, together with other information in this prospectus supplement and the accompanying prospectus, and the information and documents incorporated by reference herein and therein, and in any free writing prospectus that we have authorized for use in connection with this offering. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our common stock, and the occurrence of any of these risks might cause you to lose all or part of your investment. Moreover, the risks described are not the only ones that we face. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations. Please also read carefully the section below titled “Special Note Regarding Forward-Looking Statements.”

Management will have broad discretion as to the use of the proceeds from this offering, and may not use the proceeds effectively.

Because we have not designated the amount of net proceeds from this offering to be used for any particular purpose, our management will have broad discretion as to the application of the net proceeds from this offering and could use them for purposes other than those contemplated at the time of the offering. Our management may use the net proceeds for corporate purposes that may not improve our financial condition or market value.

The offering price per share in this offering may exceed the net tangible book value per share of our common stock outstanding prior to this offering. Assuming that an aggregate of 3,472,222 shares of our common stock are sold at a price of $2.88 per share, the last reported sale price of our common stock on the Nasdaq Capital Market on June 30, 2021, for aggregate gross proceeds of $10.0 million, and after deducting commissions and estimated offering expenses payable by us, you will experience immediate dilution of $2.34 per share, representing the difference between our as adjusted net tangible book value per share as of March 31, 2021, after giving effect to this offering, and the assumed offering price. The exercise of outstanding stock options and warrants will result in further dilution of your investment. See the section entitled “Dilution” below for a more detailed illustration of the dilution you would incur if you participate in this offering.

You may experience future dilution as a result of future equity offerings.

To raise additional capital, we may in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price per share in this offering. We may sell shares or other securities in any other offering at a price per share that is less than the price per share paid by investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders.

We do not intend to pay dividends in the foreseeable future on our common stock.

We have never paid cash dividends on our common stock and currently do not plan to pay any cash dividends in the foreseeable future on our common stock.

It is not possible to predict the aggregate proceeds resulting from sales made under the sales agreement.

Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver a placement notice to a Sales Agent at any time throughout the term of the sales agreement. The number of shares that are sold through or to the Sales Agents after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common stock during the sales period, any limits we may set with the Sales Agents in any applicable placement notice and the demand for our common stock. Because the price per share of each share sold pursuant to the sales agreement will fluctuate over time, it is not currently possible to predict the aggregate proceeds to be raised in connection with sales under the sales agreement.

Sales of common stock offered hereby will be in “at the market offerings,” and investors who buy shares at different times will likely pay different prices.

Investors who purchase shares in this offering at different times will likely pay different prices, and accordingly may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices and number of shares sold in this offering. In addition, subject to the final determination by our board of directors or any restrictions we may place in any applicable placement notice delivered to a Sales Agent, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

We may issue and sell shares of our common stock having aggregate sales proceeds of up to $10.0 million from time to time. Because there is no minimum offering amount required as a condition to this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. There can be no assurance that we will sell any shares under or fully utilize the sales agreement with the Sales Agents as a source of financing.

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. We currently intend to use the net proceeds from the sale of the securities offered hereby, if any, to acquire additional potential royalty and milestone revenue streams, for working capital and other general corporate purposes. We may also use a portion of the net proceeds to acquire or invest in businesses, products and technologies that are complementary to our own, although we have no commitments or agreements with respect to any acquisitions as of the date of this prospectus. Pending these uses, we intend to invest the net proceeds primarily in government securities and short-term, interest-bearing securities.

Our net tangible book value as of March 31, 2021 was approximately $(1.98) million, or $(0.19) per share (based on 10,610,603 shares of our common stock outstanding). Net tangible book value per share is determined by dividing our total tangible assets, less total liabilities, by the number of shares of our common stock outstanding as of March 31, 2021. Dilution with respect to net tangible book value per share represents the difference between the amount per share paid by purchasers of shares of common stock in this offering and the net tangible book value per share of our common stock immediately after this offering.

After giving effect to the assumed sale of 3,472,222 shares of our common stock in this offering at an assumed offering price of $2.88 per share, the last reported sale price of our common stock on the Nasdaq Capital Market on June 30, 2021, and after deducting estimated offering commissions and estimated offering expenses payable by us, our as adjusted net tangible book value as of March 31, 2021 would have been approximately $7.66 million, or $0.54 per share. This represents an immediate increase in net tangible book value of $0.73 per share to existing stockholders and immediate dilution of $2.34 per share to investors purchasing our common stock in this offering at the public offering price. The following table illustrates this dilution on a per share basis:

The table above assumes for illustrative purposes that an aggregate of 3,472,222 shares of our common stock are sold during the term of the sales agreement with B. Riley Securities and EF Hutton at a price of $2.88 per share, the last reported sale price of our common stock on the Nasdaq on June 30, 2021, for aggregate gross proceeds of $10.0 million. The shares subject to the sales agreement with B. Riley Securities and EF Hutton are being sold from time to time at various prices. An increase of $1.00 per share in the price at which the shares are sold from the assumed offering price of $3.88 per share shown in the table above, assuming all of our common stock in the aggregate amount of $10.0 million during the term of the sales agreement with B. Riley Securities and EF Hutton is sold at that price, would increase our adjusted net tangible book value per share after the offering to $0.58 per share and would increase the dilution per share to new investors in this offering to $3.30 per share, after deducting commissions and estimated aggregate offering expenses payable by us. A decrease of $1.00 per share in the price at which the shares are sold from the assumed offering price of $1.88 per share shown in the table above, assuming all of our common stock in the aggregate amount of $10.0 million during the term of the sales agreement with B. Riley Securities and EF Hutton is sold at that price, would decrease our adjusted net tangible book value per share after the offering to $0.48 per share and would decrease the dilution per share to new investors in this offering to $1.40 per share, after deducting commissions and estimated offering expenses payable by us. This information is supplied for illustrative purposes only and may differ based on the actual offering price and the actual number of shares offered.

The above discussion and table are based on 10,610,603 shares of our common stock issued and outstanding as of March 31, 2021 and exclude the following:

To the extent that options outstanding as of March 31, 2021 have been or are exercised, or other shares are issued, investors purchasing shares in this offering could experience further dilution. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

We have entered into a sales agreement with B. Riley Securities and EF Hutton, under which we may issue and sell from time to time up to $10.0 million of our common stock through or to the Sales Agents as agents or principals. Sales of our common stock, if any, will be made at market prices by any method that is deemed to be an “at the market offering” as defined in Rule 415 under the Securities Act.

Each time we wish to issue and sell common stock under the sales agreement, we will notify a Sales Agent of the number of shares to be issued, the dates on which such sales are anticipated to be made and any minimum price below which sales may not be made. Once we have so instructed such Sales Agent, unless the Sales Agent declines to accept the terms of such notice, the Sales Agent has agreed to use its commercially reasonable efforts consistent with its normal trading and sales practices to sell such shares up to the amount specified on such terms. The obligations of the Sales Agents under the sales agreement to sell our common stock are subject to a number of conditions that we must meet.

The Sales Agent will provide written confirmation to us following the close of trading on the Nasdaq Capital Market, each day on which common stock is sold under the sales agreement. Each confirmation will include the number of shares of common stock sold on that day, the gross sales price per share, the net proceeds to us and the compensation payable by us to the Sales Agent. Settlement for sales of common stock will occur, unless the parties agree otherwise, on the second business day that is also a trading day following the date on which any sales were made in return for payment of the net proceeds to us. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

We will pay the Sales Agents an aggregate compensation equal to 3.0% of the gross proceeds we receive from the sales of our common stock. Because there is no minimum offering amount required as a condition to close this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. In connection with the sales of our common stock on our behalf, the Sales Agents will be deemed to be “underwriters” within the meaning of the Securities Act, and the compensation paid to the Sales Agents will be deemed to be underwriting commissions or discounts. We estimate that the total expenses of the offering payable by us, excluding commissions payable to the Sales Agents under the sales agreement, will be approximately $60,000.

We will report at least quarterly the number of shares of common stock sold through or to the Sales Agents under the sales agreement, the net proceeds to us and the compensation paid by us to the Sales Agents in connection with the sales of common stock.

We have agreed in the sales agreement to provide indemnification and contribution to the Sales Agents against certain liabilities, including liabilities under the Securities Act.

The offering of our shares of common stock pursuant to the Sales Agreement will terminate as permitted therein.

To the extent required by Regulation M under the Exchange Act, the Sales Agents will not engage in any market making activities involving our common stock while the offering is ongoing under this prospectus.

The Sales Agents and their affiliates have provided, and may in the future provide, various investment banking and other financial services for us for which services they have received and, may in the future receive, customary fees and commissions.

Duane Morris LLP has passed upon the validity of the common stock offered by this prospectus. The Sales Agents are being represented in connection with this offering by The NBD Group, Inc.

Our financial statements as of and for the years ended December 31, 2020 and 2019 incorporated by reference in this prospectus have been audited by MaloneBailey, LLP, independent registered accounting firm, and are included in reliance on their report (the report on the financial statements contains an explanatory paragraph regarding the Company’s ability to continue as a going concern) given upon the authority of said firm as experts in auditing and accounting.

This prospectus is part of the registration statement on Form S-3 we filed with the SEC under the Securities Act and does not contain all the information set forth in the registration statement. Whenever a reference is made in this prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus for a copy of such contract, agreement or other document. Because we are subject to the information and reporting requirements of the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov.

The SEC allows us to incorporate by reference information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus, while information that we file later with the SEC will automatically update and supersede the information in this prospectus. We incorporate by reference into this prospectus and the registration statement of which this prospectus is a part the information or documents listed below that we have filed with the SEC:

We also incorporate by reference any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items unless such Form 8-K expressly provides to the contrary) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including those made after the date of the initial filing of the registration statement of which this prospectus is a part and prior to effectiveness of such registration statement, until we file a post-effective amendment that indicates the termination of the offering of the securities made by this prospectus, which will become a part of this prospectus from the date that such documents are filed with the SEC. Information in such future filings updates and supplements the information provided in this prospectus. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later-filed document modify or replace such earlier statements. We will furnish without charge to each person, including any beneficial owner, to whom a prospectus is delivered, upon written or oral request, a copy of any or all of the documents incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents to:

We may offer and sell, from time to time in one or more offerings, any combination of common stock, preferred stock, debt securities, warrants, or units having a maximum aggregate offering price of $100,000,000. When we decide to sell a particular class or series of securities, we will provide specific terms of the offered securities in a prospectus supplement.

The prospectus supplement may also add, update or change information contained in or incorporated by reference into this prospectus. However, no prospectus supplement shall offer a security that is not registered and described in this prospectus at the time of its effectiveness. You should read this prospectus and any prospectus supplement, as well as the documents incorporated by reference or deemed to be incorporated by reference into this prospectus, carefully before you invest. This prospectus may not be used to offer or sell our securities unless accompanied by a prospectus supplement relating to the offered securities.

Our common stock is listed on the Nasdaq Capital Market under the symbol “PTIX” and our Warrants are listed on the Nasdaq Capital Market under the symbol “PTIXW.” On June 3, 2021, the last reported sale price of our common stock on the Nasdaq Capital Market was $2.60 per share.

These securities may be sold directly by us, through dealers or agents designated from time to time, to or through underwriters or through a combination of these methods. See “Plan of Distribution” in this prospectus. We may also describe the plan of distribution for any particular offering of our securities in a prospectus supplement. If any agents, underwriters or dealers are involved in the sale of any securities in respect of which this prospectus is being delivered, we will disclose their names and the nature of our arrangements with them in a prospectus supplement. The net proceeds we expect to receive from any such sale will also be included in a prospectus supplement.

An investment in our securities involves a high degree of risk. See the sections entitled “Risk Factors” in our most recent Annual Report on Form 10-K and in any Quarterly Report on Form 10-Q, as well as in any prospectus supplement related to these specific offerings.

This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, using a “shelf” registration process. Under this shelf registration statement, we may sell from time to time in one or more offerings up to a total dollar amount of $100,000,000 of common stock and preferred stock, depositary shares representing preferred stock and various series of debt securities, rights, warrants to purchase any of such securities, and/or units, either individually or in combination with other securities as described in this prospectus. Each time we sell any type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add, update or change in a prospectus supplement or free writing prospectus any of the information contained in this prospectus or in documents we have incorporated by reference into this prospectus. This prospectus, together with any applicable prospectus supplement or free writing prospectus and the documents incorporated by reference into this prospectus, include all material information relating to this offering. You should carefully read both this prospectus and any applicable prospectus supplement and any related free writing prospectus together with the additional information described under “Where You Can Find More Information” before buying securities in this offering.

You should rely only on the information contained in, or incorporated by reference into, this prospectus and the applicable prospectus supplement, along with the information contained in any free writing prospectuses we have authorized for use in connection with a specific offering. We have not authorized anyone to provide you with different or additional information. We are not making an offer to sell or seeking an offer to buy securities under this prospectus or any applicable prospectus supplement or free writing prospectus in any jurisdiction where the offer or sale is not permitted. The information contained in this prospectus, any applicable prospectus supplement or free writing prospectus and the documents incorporated by reference herein and therein are accurate only as of their respective dates, regardless of the time of delivery of this prospectus or any sale of a security.

The information appearing in this prospectus, any applicable prospectus supplement and any related free writing prospectus is accurate only as of the date on the front of the document and any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, the applicable prospectus supplement or any related free writing prospectus, or any sale of a security. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the section entitled “Where You Can Find More Information.”

We may sell securities through underwriters or dealers, through agents, directly to purchasers or through any combination of these methods. We and our agents reserve the sole right to accept or reject in whole or in part any proposed purchase of securities. The prospectus supplement, which we will prepare and file with the SEC each time we offer securities, will set forth the names of any underwriters, agents or others involved in the sale of securities, and any applicable fee, commission or discount arrangements with them. See “Plan of Distribution.”

In this prospectus, unless otherwise indicated, “our company,” “Protagenic,” “we,” “us” or “our” refer to Protagenic Therapeutics, Inc., a Delaware corporation, and its consolidated subsidiaries.

PROSPECTUS SUMMARY

This prospectus summary highlights certain information about our company and other information contained elsewhere in this prospectus or in documents incorporated by reference. This summary does not contain all of the information that you should consider before making an investment decision. You should carefully read the entire prospectus, any prospectus supplement, including the section entitled “Risk Factors” and the documents incorporated by reference into this prospectus, before making an investment decision.

The Offering

This prospectus is part of a Registration Statement that we filed with the SEC utilizing a shelf registration process. Under this shelf registration process, we may sell any combination of:

●	common stock;
●	preferred stock;
●	debt securities, in one or more series;
●	right to purchase common stock of other securities; and/or
●	warrant to purchase common stock of other securities; and/or

in one or more offerings up to a total dollar amount of $100,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that specific offering and include a discussion of any risk factors or other special considerations that apply to those securities. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with the additional information described under the heading “Where You Can Find More Information.”

Our Company

Overview

Risk Factors Summary

Below is a summary of material factors that make an investment in our securities speculative or risky. Importantly, this summary does not address all of the risks and uncertainties that we face. Additional discussion of the risks and uncertainties summarized in this risk factor summary, as well as other risks and uncertainties that we face, can be found under “Risk Factors” in Part I, Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2020. The below summary is qualified in its entirety by that more complete discussion of such risks and uncertainties. You should consider carefully the risks and uncertainties described under “Risk Factors” in Part I, Item 1A of our most recent Annual Report on Form 10-K as part of your evaluation of the risks associated with an investment in our securities.

Risks Related to Our Financial Condition and Capital Requirements

● The Company’s financial statements have been prepared on a going concern basis, and do not include adjustments that might be necessary if the Company is unable to continue as a going concern.

● If we continue to incur operating losses and fail to obtain the capital necessary to fund our operations, we will be unable to advance our development programs, complete our clinical trials, or bring products to market, or may be forced to reduce or cease operations entirely. In addition, any capital obtained by us may be obtained on terms that are unfavorable to us, our investors, or both.

● Unstable market and economic conditions may have serious adverse consequences on our ability to raise funds, which may cause us to cease or delay our operations.

● Covid-19 could adversely impact our business, including our clinical trials, and financial condition.

Risks Related to Clinical Development and Regulatory Approval

● Our results to date provide no basis for predicting whether any of our product candidates will be safe or effective, or receive regulatory approval.

● We may not be able to initiate and complete preclinical studies and clinical trials for our product candidates which could adversely affect our business.

● If we experience delays or difficulties in the enrollment of subjects to our clinical trials, our receipt of necessary regulatory approvals could be delayed or prevented, which could materially affect our financial condition.

● If the market opportunities for our current and potential future drug candidates are smaller than we believe they are, our ability to generate product revenues will be adversely affected and our business may suffer.

Risks Related to Our Reliance on Third Parties

● We have no experience in sales, marketing and distribution and may have to enter into agreements with third parties to perform these functions, which could prevent us from successfully commercializing our product candidates.

● Data provided by collaborators and other parties upon which we rely have not been independently verified and could turn out to be inaccurate, misleading, or incomplete.

● We rely on third parties to conduct our non-clinical studies and our clinical trials. If these third parties do not successfully carry out their contractual duties or meet expected deadlines, we may be unable to obtain regulatory approval for or commercialize our current product candidates or any future products, on a timely basis or at all, and our financial condition will be adversely affected.

Risks Related to Commercialization of Our Product Candidates

● We have no experience as a company in commercializing any product. If we fail to obtain commercial expertise, upon product approval by regulatory agencies, our product launch and revenues could be delayed.

● We may not be able to gain market acceptance of our product candidates, which would prevent us from becoming profitable.

● We may not be able to manufacture our product candidates in clinical or commercial quantities, which would prevent us from commercializing our product candidates.

● Disputes under key agreements or conflicts of interest with our scientific advisors or clinical investigators could delay or prevent development or commercialization of our product candidates.

Risks Related to Our Intellectual Property

● We may not be able to maintain our exclusive worldwide license to use and develop PT00114 which could materially affect our business plan.

Risks Related to Our Business Operations and Industry

● If we are not able to retain our current senior management team and our scientific advisors or continue to attract and retain qualified scientific, technical and business personnel, our business will suffer.

● We may encounter difficulties in managing our growth, which could adversely affect our operations.

● Healthcare reform measures could adversely affect our business.

● Our business and operations are vulnerable to computer system failures, cyber-attacks or deficiencies in our cyber-security, which could increase our expenses, divert the attention of our management and key personnel away from our business operations and adversely affect our results of operations.

● Failure to comply with health and data protection laws and regulations could lead to government enforcement actions (which could include civil or criminal penalties), private litigation or adverse publicity and could negatively affect our operating results and business.

● If we, our CROs or our IT vendors experience security or data privacy breaches or other unauthorized or improper access to, use of, or destruction of personal data, we may face costs, significant liabilities, harm to our brand and business disruption.

● If we do not comply with laws regulating the protection of the environment and health and human safety, our business could be adversely affected.

Risks Associated to our Common Stock

● Our common stock is a “Penny Stock” subject to specific rules governing its sale to investors that could impact its liquidity.

● There is no recent trading activity in our common stock and there is no assurance that an active market will develop in the future.

● Our ability to list on Nasdaq will require raising significant capital; failure to qualify to trade on Nasdaq will make it more difficult to raise capital.

● The market price of our common stock may be volatile, which could lead to losses by investors and costly securities litigation.

● If we fail to maintain an effective system of internal controls, we may not be able to accurately report our financial results or detect fraud. Consequently, investors could lose confidence in our financial reporting and this may decrease the trading price of our stock.

● Investors may experience dilution of their ownership interests because of the future issuance of additional shares of our common stock.

● Our common stock is controlled by insiders.

● We do not intend to pay dividends for the foreseeable future and may never pay dividends.

Our certificate of incorporation allows for our board to create new series of preferred stock without further approval by our stockholders, which could adversely affect the rights of the holders of our common stock.

Corporate Information

We are a Delaware corporation with one subsidiary, Protagenic Therapeutics Canada (2006) Inc., a corporation formed in 2006 under the laws of the Province of Ontario, Canada. Our principal offices are located at 149 Fifth Avenue, New York, New York 10010. Our telephone number is (212) 994-8200. The inclusion of our website address does not include or incorporate by reference into this prospectus supplement or the accompanying prospectus any information on, or accessible through, our website. Our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, together with amendments to these reports, are available on the “Investor Relations” section of our website, free of charge, as soon as reasonably practicable after such material is electronically filed with, or furnished to, the U.S. Securities and Exchange Commission (“SEC”).

The Securities We May Offer

We may offer shares of our common stock and preferred stock, depositary shares representing a fractional interest in a share of preferred stock, various series of debt securities, rights, warrants to purchase any of such securities, and/or units either individually or in combination with other securities, with a total value of up to $100,000,000 from time to time under this prospectus, together with the applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined at the time of any offering. We may also offer common stock, preferred stock and/or debt securities upon the exercise of the rights or warrants. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including.

Investing in our securities involves risk. The prospectus supplement applicable to a particular offering of securities will contain a discussion of the risks applicable to an investment in Protagenic and to the particular types of securities that we are offering under that prospectus supplement. Before making an investment decision, you should carefully consider the risks described under “Risk Factors” in the applicable prospectus supplement and the risks described in our most recent Annual Report on Form 10-K for the year ended December 31, 2020, as amended from time to time, which is incorporated herein by reference, or any updates in our Quarterly Reports on Form 10-Q, together with all of the other information appearing in or incorporated by reference into this prospectus and any applicable prospectus supplement, in light of your particular investment objectives and financial circumstances. Our business, financial condition or results of operations could be materially adversely affected by any of these risks. The trading price of our securities could decline due to any of these risks, and you may lose all or part of your investment.

This prospectus contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or Securities Act, and Section 21E of the Securities Exchange Act of 1934, or Exchange Act. Forward-looking statements reflect the current view about future events. When used in this prospectus, the words “anticipate,” “believe,” “estimate,” “expect,” “future,” “intend,” “plan,” or the negative of these terms and similar expressions, as they relate to us or our management, identify forward-looking statements. Such statements, include, but are not limited to, statements contained in this prospectus relating to our business strategy, our future operating results and liquidity and capital resources outlook. Forward-looking statements are based on our current expectations and assumptions regarding our business, the economy and other future conditions. Because forward–looking statements relate to the future, they are subject to inherent uncertainties, risks and changes in circumstances that are difficult to predict. Our actual results may differ materially from those contemplated by the forward-looking statements. They are neither statements of historical fact nor guarantees of assurance of future performance. We caution you therefore against relying on any of these forward-looking statements. Important factors that could cause actual results to differ materially from those in the forward-looking statements include, without limitation, the results of clinical trials and the regulatory approval process; our ability to raise capital to fund continuing operations; market acceptance of any products that may be approved for commercialization; our ability to protect our intellectual property rights; the impact of any infringement actions or other litigation brought against us; competition from other providers and products; our ability to develop and commercialize new and improved products and services; changes in government regulation; our ability to complete capital raising transactions; and other factors (including the risks contained in the section entitled “Risk Factors” of the applicable prospectus supplement) relating to our industry, our operations and results of operations. Should one or more of these risks or uncertainties materialize, or should the underlying assumptions prove incorrect, actual results may differ significantly from those anticipated, believed, estimated, expected, intended or planned.

Factors or events that could cause our actual results to differ may emerge from time to time, and it is not possible for us to predict all of them. We cannot guarantee future results, levels of activity, performance or achievements. Except as required by applicable law, including the securities laws of the United States, we do not intend to update any of the forward-looking statements to conform these statements to actual results.

We have never paid any cash dividends on our common stock. We anticipate that we will retain funds and future earnings to support operations and to finance the growth and development of our business. Therefore, we do not expect to pay cash dividends in the foreseeable future following this offering, if at all. Any future determination to pay dividends will be at the discretion of our board of directors and will depend on our financial condition, results of operations, capital requirements and other factors that our board of directors deems relevant. In addition, the terms of any future debt or credit financings may preclude us from paying dividends.

Except as otherwise provided in the applicable prospectus supplement, we intend to use the net proceeds from the sale of the securities covered by this prospectus for general corporate purposes, which may include, but is not limited to, working capital, capital expenditures, research and development clinical trial expenditures, acquisitions of additional companies or technologies and investments. We may temporarily invest the net proceeds in investment-grade, interest-bearing securities until they are used for their stated purpose. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds.

The following is a description of our Common Stock, $0.0001 par value (the “Common Stock”) and Preferred Stock, $0.000001 par value (the “Preferred Stock”). The Common Stock is the only security of the Company registered pursuant to Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

General. We are authorized to issue is 120,000,000 shares of all classes of capital stock, of which 100,000,000 shares are Common Stock, $0.001 par value per share, and 20,000,000 shares are Preferred Stock, $0.000001 par value per share. Our capital is stated in U.S. dollars. As of May 14, 2021, we had 14,643,780 outstanding shares of Common Stock.

Voting. The holders of our common stock are entitled to one vote for each share held of record on all matters on which the holders are entitled to vote (or consent pursuant to written consent).

Dividends. The holders of our common stock are entitled to receive, ratably, dividends only if, when and as declared by our board of directors out of funds legally available therefor and after provision is made for each class of capital stock having preference over the common stock. We have never declared or paid dividends. We do not intend to pay cash dividends on our common stock for the foreseeable future, but currently intend to retain any future earnings to fund the development and growth of our business. The payment of dividends if any, on our common stock will rest solely within the discretion of our board of directors and will depend, among other things, upon our earnings, capital requirements, financial condition, and other relevant factors.

Liquidation Rights. In the event of our liquidation, dissolution or winding-up, the holders of our common stock are entitled to share, ratably, in all assets remaining available for distribution after payment of all liabilities and after provision is made for each class of capital stock having preference over the common stock.

Conversion Rights. The holders of our common stock have no conversion rights.

Preemptive and Similar Rights. The holders of our common stock have no preemptive or similar rights.

Redemption/Put Rights. There are no redemption or sinking fund provisions applicable to the common stock. All of the outstanding shares of our common stock are fully-paid and non-assessable.

Anti-Takeover Effect of Delaware Law, Certain Charter and Bylaw Provisions

In addition to the provisions included in our Third Amended and Restated Certificate of Incorporation and Bylaws, we are subject to the provisions of Section 203 of the General Corporation Law of the State of Delaware, an anti-takeover law. In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless the business combination is approved in the following prescribed manner:

Generally, for purposes of Section 203, a “business combination” includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested stockholder. An “interested stockholder” is a person who, together with affiliates and associates, owns or, within three years prior to the determination of interested stockholder status, owned 15% or more of a corporation’s outstanding voting securities.

American Stock Transfer & Trust Company, LLC is the transfer agent and registrar for our common stock.

Under the terms of our Third Amended and Restated Certificate of Incorporation, our board of directors have the authority, without further action by our stockholders, to issue up to 20,000,000 shares of Preferred Stock in one or more series, to establish from time to time the number of shares to be included in each such series, to fix the rights, preferences and privileges of the shares of each wholly unissued series and any qualifications, limitations or restrictions thereon, and to increase or decrease the number of shares of any such series, but not below the number of shares of such series then outstanding. The powers, preferences and relative, participating, optional and other special rights of each series of Preferred Stock, and the qualifications, limitations or restrictions thereof, if any, may differ from those of any and all other series at any time outstanding.

Our board of directors may authorize the issuance of Preferred Stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of our Common Stock. The purpose of authorizing our board of directors to issue Preferred Stock and determine its rights and preferences is to eliminate delays associated with a stockholder vote on specific issuances. The issuance of Preferred Stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring or preventing a change in control of us and may adversely affect the market price of our Common Stock and the voting and other rights of the holders of our Common Stock. It is not possible to state the actual effect of the issuance of any shares of Preferred Stock on the rights of holders of Common Stock until the board of directors determines the specific rights attached to that Preferred Stock.

We may offer depositary shares, which will be evidenced by depositary receipts, representing fractional interests in shares of preferred stock of any series. In connection with the issuance of any depositary shares, we will enter into a deposit agreement with a bank or trust company, as depositary, which will be named in the applicable prospectus supplement. The following briefly summarizes the material provisions of the deposit agreement and of the depositary shares and depositary receipts, other than pricing and related terms disclosed for a particular issuance in an accompanying prospectus supplement. This description is not complete and is subject to, and qualified in its entirety by reference to, all provisions of the deposit agreement, depositary shares and depositary receipts. You should read the particular terms of any depositary shares and any depositary receipts that we offer and any deposit agreement relating to a particular series of preferred stock described in more detail in a prospectus supplement. The prospectus supplement will also state whether any of the generalized provisions summarized below do not apply to the depositary shares or depositary receipts being offered.

We may, at our option, elect to offer fractional shares of preferred stock, rather than full shares of preferred stock. In such event, we will issue receipts for depositary shares, each of which will represent a fraction of a share of a particular series of preferred stock. For a description of our preferred stock, see “Description of Capital Stock–Preferred Stock.”

The shares of any series of preferred stock represented by depositary shares will be deposited under a deposit agreement between us and the depositary we select. Each owner of a depositary share will be entitled to all the rights and preferences of the underlying preferred stock, including any dividend, voting, redemption, conversion and liquidation rights described in the particular prospectus supplement, in proportion to the applicable fraction of a share of preferred stock represented by such depositary share.

The depositary shares will be evidenced by depositary receipts issued pursuant to the deposit agreement. Depositary receipts will be distributed to those persons purchasing the fractional shares of preferred stock in accordance with the terms of the applicable prospectus supplement.

The preferred stock depositary will distribute all cash dividends or other cash distributions, if any, received in respect of the deposited preferred stock to the record holders of depositary shares relating to the preferred stock in proportion to the number of depositary shares owned by such holders on the relevant record date.

In the case of a distribution other than in cash, the preferred stock depositary will distribute any property received by it other than cash to the record holders of depositary shares entitled to receive it in proportion to the number of depositary shares owned by such holder. If the preferred stock depositary determines that it is not feasible to make such a distribution, it may, with our approval, sell the property and distribute the net proceeds from the sale to the holders of the depositary shares.

The amounts distributed in any such distribution, whether in cash or otherwise, will be reduced by any amount required to be withheld by us or the preferred stock depositary on account of taxes.

Unless otherwise indicated in the applicable prospectus supplement and unless the related depositary shares have been called for redemption, when a holder surrenders depositary receipts at the office of the preferred stock depositary maintained for that purpose, and pays any necessary taxes, charges or other fees, the holder will be entitled to receive the number of whole shares of the related series of preferred stock, and any money or other property, if any, represented by the holder’s depositary shares. Once a holder exchanges depositary shares for whole shares of preferred stock, that holder generally cannot “re-deposit” these shares of preferred stock with the preferred stock depositary, or exchange them for depositary shares. If a holder delivers depositary receipts that represent a number of depositary shares other than a whole number of shares of preferred stock for redemption or exchange, the preferred stock depositary will issue a new depositary receipt to the holder that evidences the remainder of depositary shares at the same time that the preferred stock is withdrawn.

If a series of preferred stock represented by depositary shares is to be redeemed, the depositary shares will be redeemed from the proceeds received by the preferred stock depositary resulting from the redemption, in whole or in part, of that series of preferred stock. The depositary shares will be redeemed by the preferred stock depositary at a price per depositary share equal to the applicable fraction of the redemption price per share payable in respect of the shares of preferred stock redeemed.

Whenever we redeem shares of preferred stock held by the preferred stock depositary, the preferred stock depositary will redeem, as of the same date, the number of depositary shares representing shares of preferred stock redeemed. If fewer than all the depositary shares are to be redeemed, the depositary shares to be redeemed will be selected by the preferred stock depositary by lot or ratably or by any other equitable method, in each case as we may determine.

If a series of preferred stock represented by depositary shares is to be converted or exchanged, the holder of depositary receipts representing the shares of preferred stock being converted or exchanged will have the right or obligation to convert or exchange the depositary shares evidenced by the depositary receipts.

After the redemption, conversion or exchange date, the depositary shares called for redemption, conversion or exchange will no longer be outstanding. When the depositary shares are no longer outstanding, all rights of the holders will end, except the right to receive money, securities or other property payable upon redemption, conversion or exchange.

Upon receipt of notice of any meeting at which the holders of any series of deposited preferred stock are entitled to vote, the preferred stock depositary will mail the information contained in the notice of meeting to the record holders of the depositary receipts evidencing the depositary shares relating to that series of preferred stock. Each record holder of the depositary receipts on the record date will be entitled to instruct the preferred stock depositary to vote the amount of the preferred stock represented by the holder’s depositary shares. The preferred stock depositary will try, if practical, to vote the amount of such series of preferred stock represented by such depositary shares in accordance with such instructions.

We will agree to take all reasonable actions that the preferred stock depositary determines are necessary to enable the preferred stock depositary to vote as instructed. The preferred stock depositary will abstain from voting shares of any series of preferred stock held by it for which it does not receive specific instructions from the holders of depositary shares representing those preferred shares.

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time be amended by agreement between us and the preferred stock depositary. However, any amendment that materially and adversely alters any existing right of the holders of depositary receipts will not be effective unless the amendment has been approved by the holders of depositary receipts representing at least a majority of the depositary shares then outstanding. Additionally, in the case of amendments relating to or affecting rights to receive dividends or distributions or voting or redemption rights, approval is also required by the holders of depositary receipts representing not less than a specified percentage or all of the depositary shares of such series or class then outstanding, as provided in the applicable prospectus supplement. Every holder of an outstanding depositary receipt at the time any such amendment becomes effective will be deemed, by continuing to hold the depositary receipt, to consent and agree to the amendment and to be bound by the deposit agreement, as amended.

We may direct the preferred stock depositary to terminate the deposit agreement at any time by mailing notice of termination to the record holders of the depositary receipts then outstanding at least 30 days prior to the date fixed for termination. Upon termination, the preferred stock depositary will deliver to each holder of depositary receipts, upon surrender of those receipts, such number of whole shares of the series of preferred stock represented by the depositary shares together with cash in lieu of any fractional shares, to the extent we have deposited cash for payment in lieu of fractional shares with the preferred stock depositary. In addition, the deposit agreement will automatically terminate if:

We will pay all transfer and other taxes and governmental charges arising solely from the existence of the depositary arrangements. We also will pay charges of the preferred stock depositary in connection with the initial deposit of preferred stock and any redemption of preferred stock. Holders of depositary receipts will pay other transfer and other taxes and governmental charges and such other charges, including a fee for the withdrawal of shares of preferred stock upon surrender of depositary receipts, as are expressly provided in the deposit agreement to be for their accounts.

Prospective purchasers of depositary shares should be aware that special tax, accounting and other issues may be applicable to instruments such as depositary shares.

The preferred stock depositary may resign at any time by delivering to us notice of its intent to do so, and we may at any time remove the preferred stock depositary, any such resignation or removal to take effect upon the appointment of a successor preferred stock depositary meeting the requirements specified in the deposit agreement and its acceptance of such appointment.

The preferred stock depositary will forward all reports and communications from us which are delivered to the preferred stock depositary and which we are required to furnish to the holders of the deposited preferred stock.

Neither we nor the preferred stock depositary will be liable if we are or the preferred stock depositary is prevented or delayed by law or any circumstances beyond our or its control in performing our or its obligations under the deposit agreement. Our obligations and the obligations of the preferred stock depositary under the deposit agreement will be limited to performance in good faith of the duties under the deposit agreement, and we and the preferred stock depositary will not be obligated to prosecute or defend any legal proceeding in respect of any depositary shares, depositary receipts or shares of preferred stock unless satisfactory indemnity is furnished. We and the preferred stock depositary may rely upon written advice of counsel or accountants, or upon information provided by holders of depositary receipts or other persons believed to be competent and on documents believed to be genuine.

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act”). We have filed the form of indenture as an exhibit to the Registration Statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the Registration Statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.

The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with OID for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company (“DTC”), or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

The complete terms of the rights will be contained in the rights agreements we enter into with rights agents. These documents will be included or incorporated by reference as exhibits to the registration statement of which this prospectus is a part. You should read the rights agreements and any related documents. You also should read the prospectus supplement, which will contain additional information and which may update or change some of the information below.

This section describes the general terms of the rights to purchase common stock or other securities that we may offer to stockholders using this prospectus. Further terms of the rights will be stated in the applicable prospectus supplement (or applicable free writing prospectus). The following description and any description of the rights in a prospectus supplement (or applicable free writing prospectus) may not be complete and is subject to and qualified in its entirety by reference to the terms of any agreement relating to the rights.

Rights may be issued independently or together with any other security and may or may not be transferable. As part of any rights offering, we may enter into a standby underwriting or other arrangement under which the underwriters or any other person would purchase any securities that are not purchased in such rights offering. If we issue rights, each series of rights will be issued under a separate rights agreement to be entered into between us and a bank or trust company, as rights agent, that will be named in the applicable prospectus supplement. Further terms of the rights will be stated in the applicable prospectus supplement. The rights agent will act solely as our agent and will not assume any obligation to any holders of rights certificates or beneficial owners of rights. The rights agreements and rights certificates will be filed with the SEC as an exhibit to the registration statement of which this prospectus is a part or as an exhibit to a filing incorporated by reference in the registration statement. See “Where You Can Find Additional Information” for information on how to obtain copies of the rights agreements and rights certificates.

The prospectus supplement relating to any rights we offer will describe the specific terms of the offering and the rights, including the record date for stockholders entitled to the rights distribution, the number of rights issued and the number of shares of common stock that may be purchased upon exercise of the rights, the exercise price of the rights, the date on which the rights will become effective and the date on which the rights will expire, and any applicable U.S. federal income tax considerations.

In general, a right entitles the holder to purchase for cash a specific number of shares of common stock or other securities at a specified exercise price. The rights are normally issued to stockholders as of a specific record date, may be exercised only for a limited period of time and become void following the expiration of such period. If we determine to issue rights, we will accompany this prospectus with a prospectus supplement that will describe, among other things:

If fewer than all of the rights issued in any rights offering are exercised, we may offer any unsubscribed securities directly to persons other than stockholders, to or through agents, underwriters or dealers or through a combination of such methods, including pursuant to standby arrangements, as described in the applicable prospectus supplement. After the close of business on the expiration date, all unexercised rights will become void.

The following description, together with the additional information we may include in any applicable prospectus supplement and free writing prospectus, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the Registration Statement of which this prospectus is a part. We will file as exhibits to the Registration Statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that describes the terms of the particular series of warrants we are offering and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant and/or warrant agreement and warrant certificates, as applicable, and any supplemental agreements that contain the terms of the warrants.

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including:

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. The warrants may be exercised as set forth in the prospectus supplement relating to the warrants offered. Unless we otherwise specify in the applicable prospectus supplement, the warrants may be exercised at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement relating to the warrants offered thereby. After the close of business on the expiration date, unexercised warrants will become void.

Upon receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office indicated in the applicable prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If less than all of the warrants (or the warrants represented by such warrant certificate) are exercised, then we will issue a new warrant or warrant certificate, as applicable, for the remaining warrants.

Unless we otherwise specify in the applicable prospectus supplement, the warrants and any warrant agreements will be governed by and construed in accordance with the laws of the State of New York.

Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

We may issue units comprised of one or more of the other securities described in this prospectus or in any prospectus supplement in any combination. Each unit will be issued so that the holder of the unit is also the holder, with the rights and obligations of a holder, of each security included in the unit. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date or upon the occurrence of a specified event or occurrence.

The applicable prospectus supplement relating to units offered under this prospectus will describe the following terms, where applicable, of such units:

We may sell the securities being offered pursuant to this prospectus to or through underwriters, through dealers, through agents, or directly to one or more purchasers or through a combination of these methods. The applicable prospectus supplement will describe the terms of the offering of the securities, including:

We may distribute the securities from time to time in one or more transactions at:

Only underwriters named in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.

If underwriters are used in an offering, we will execute an underwriting agreement with such underwriters and will specify the name of each underwriter and the terms of the transaction (including any underwriting discounts and other terms constituting compensation of the underwriters and any dealers) in a prospectus supplement. The securities may be offered to the public either through underwriting syndicates represented by managing underwriters or directly by one or more investment banking firms or others, as designated. If an underwriting syndicate is used, the managing underwriter(s) will be specified on the cover of the prospectus supplement. If underwriters are used in the sale, the offered securities will be acquired by the underwriters for their own accounts and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Any public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time. Unless otherwise set forth in the prospectus supplement, the obligations of the underwriters to purchase the offered securities will be subject to conditions precedent, and the underwriters will be obligated to purchase all of the offered securities, if any are purchased.

We may grant to the underwriters options to purchase additional securities to cover over-allotments, if any, at the public offering price, with additional underwriting commissions or discounts, as may be set forth in a related prospectus supplement. The terms of any over-allotment option will be set forth in the prospectus supplement for those securities.

If we use a dealer in the sale of the securities being offered pursuant to this prospectus or any prospectus supplement, we will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale. The names of the dealers and the terms of the transaction will be specified in a prospectus supplement.

We may sell the securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement.

We may authorize agents or underwriters to solicit offers by institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

In connection with the sale of the securities, underwriters, dealers or agents may receive compensation from us or from purchasers of the securities for whom they act as agents, in the form of discounts, concessions or commissions. Underwriters may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters or commissions from the purchasers for whom they may act as agents. Underwriters, dealers and agents that participate in the distribution of the securities, and any institutional investors or others that purchase securities directly for the purpose of resale or distribution, may be deemed to be underwriters, and any discounts or commissions received by them from us and any profit on the resale of the common stock by them may be deemed to be underwriting discounts and commissions under the Securities Act. No FINRA member firm may receive compensation in excess of that allowable under FINRA rules, including Rule 5110, in connection with the offering of the securities.

We may provide agents, underwriters and other purchasers with indemnification against particular civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents, underwriters or other purchasers may make with respect to such liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

To facilitate the public offering of a series of securities, persons participating in the offering may engage in transactions that stabilize, maintain, or otherwise affect the market price of the securities. This may include over-allotments or short sales of the securities, which involves the sale by persons participating in the offering of more securities than have been sold to them by us. In exercising the over-allotment option granted to those persons. In addition, those persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to underwriters or dealers participating in any such offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. Such transactions, if commenced, may be discontinued at any time. We make no representation or prediction as to the direction or magnitude of any effect that the transactions described above, if implemented, may have on the price of our securities.

Unless otherwise specified in the applicable prospectus supplement, any common stock sold pursuant to a prospectus supplement will be eligible for trading on Nasdaq Capital Market. Any underwriters to whom securities are sold by us for public offering and sale may make a market in the securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice.

We may engage in at the market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. In addition, we may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and they may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in these sale transactions will be an underwriter and will be identified in the applicable prospectus supplement. In addition, we may otherwise loan or pledge securities to a financial institution or other third party that in turn may sell the securities short using this prospectus. The financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

We will file a prospectus supplement to describe the terms of any offering of our securities covered by this prospectus. The prospectus supplement will disclose:

We will bear all or substantially all of the costs, expenses and fees in connection with the registration of our securities under this prospectus. The underwriters, dealers and agents may engage in transactions with us, or perform services for us, in the ordinary course of business.

In order to comply with the securities laws of some states, if applicable, the securities offered pursuant to this prospectus will be sold in those states only through registered or licensed brokers or dealers. In addition, in some states securities may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and complied with.

Unless otherwise indicated in the applicable prospectus supplement, the validity of the securities offered hereby will be passed upon for us by Duane Morris LLP, New York, New York. If the validity of the securities offered hereby in connection with offerings made pursuant to this prospectus are passed upon by counsel for the underwriters, dealers or agents, if any, such counsel will be named in the prospectus supplement relating to such offering.

LIMITATION ON LIABILITY AND DISCLOSURE OF COMMISSION POSITION ON
INDEMNIFICATION FOR SECURITIES ACT LIABILITIES

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to our directors, officers and controlling persons pursuant to the foregoing provisions, or otherwise, we have been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, we will, unless in the opinion of our counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by us is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

This prospectus and any subsequent prospectus supplements do not contain all of the information in the Registration Statement. We have omitted from this prospectus some parts of the Registration Statement as permitted by the rules and regulations of the SEC. Statements in this prospectus concerning any document we have filed as an exhibit to the Registration Statement or that we otherwise filed with the SEC are not intended to be comprehensive and are qualified in their entirety by reference to these filings. In addition, we file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains an Internet site that contains reports, proxy and information statements and other information that we file electronically with the SEC, including us. The SEC’s Internet site can be found at http://www.sec.gov. In addition, we make available on or through our Internet site copies of these reports as soon as reasonably practicable after we electronically file or furnished them to the SEC. Our Internet site can be found at http:www.protagenic.com. Our website is not a part of this prospectus.

We have elected to incorporate certain information by reference into this prospectus. By incorporating by reference, we can disclose important information to you by referring you to other documents we have filed or will file with the SEC. The information incorporated by reference is deemed to be part of this prospectus, except for information incorporated by reference that is superseded by information contained in this prospectus. This means that you must look at all of the SEC filings that we incorporate by reference to determine if any statements in the prospectus or any document previously incorporated by reference have been modified or superseded. This prospectus incorporates by reference the documents set forth below that we have previously filed with the SEC under the Securities Exchange Act of 1934, as amended (the “Exchange Act”):

	Page
ABOUT THIS PROSPECTUS	S-ii

PROSPECTUS SUMMARY	S-1

RISK FACTORS	S-3

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	S-iii

USE OF PROCEEDS	S-4

DILUTION	S-5

PLAN OF DISTRIBUTION	S-6

LEGAL MATTERS	S-7

EXPERTS	S-7

WHERE YOU CAN FIND MORE INFORMATION	S-7

INFORMATION INCORPORATED BY REFERENCE	S-7

		Page
ABOUT THIS PROSPECTUS		1

PROSPECTUS SUMMARY		2

RISK FACTORS		5

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS		6

USE OF PROCEEDS		7

DESCRIPTION OF CAPITAL STOCK		8

DESCRIPTION OF DEPOSITARY SHARES		10

DESCRIPTION OF DEBT SECURITIES		13

DESCRIPTION OF WARRANTS		21

PLAN OF DISTRIBUTION		23

LEGAL MATTERS		25

EXPERTS		25

LIMITATION ON LIABILITY AND DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITIES		25

WHERE YOU CAN FIND MORE INFORMATION		25

INFORMATION INCORPORATED BY REFERENCE		26

Assumed public offering price per share				$	2.88
Net tangible book value per share of as March 31, 2021	$	(0.19	)
Increase per share attributable to this offering		0.73
As adjusted net tangible book value per share as of March 31, 2021, after giving effect to this offering					0.54
Dilution per share to new investors purchasing our common stock in this offering				$	(2.34	)

		PAGE
ABOUT THIS PROSPECTUS		1
PROSPECTUS SUMMARY		2
RISK FACTORS		5
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS		6
USE OF PROCEEDS		7
DESCRIPTION OF CAPITAL STOCK		8
DESCRIPTION OF DEPOSITARY SHARES		10
DESCRIPTION OF DEBT SECURITIES		13
DESCRIPTION OF WARRANTS		21
PLAN OF DISTRIBUTION		23
LEGAL MATTERS		25
EXPERTS		25
LIMITATION ON LIABILITY AND DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITIES		25
WHERE YOU CAN FIND MORE INFORMATION		25
INFORMATION INCORPORATED BY REFERENCE		26

B. Riley Securities	EF Hutton,
	division of Benchmark Investments, LLC

	●	5,673,861 shares of our common stock issuable upon the exercise of stock options outstanding as of March 31, 2021, at a weighted average exercise price of $1.76 per share; and

	●	3,483,767 shares of our common stock issuable upon the exercise of warrants outstanding as of March 31, 2021, at a weighted average exercise price of $1.03 per share; and

	●	1,694,183 shares of our common stock issuable upon conversion of principal and accrued interest underlying the convertible notes, outstanding as of March 31, 2021, assuming a conversion date of March 31, 2021, and any additional shares of our common stock issuable as a result of any anti-dilution adjustments under the convertible notes; and

	●	4,868,623 shares of our common stock reserved for future issuance under our 2016 equity incentive plan as well as any automatic increases in the number of shares of our common stock reserved for future issuance under this plan; and

	●	3,259,500 shares of common stock issued in connection with the offering (which includes 79,500 restricted shares issued to the underwriters as compensation) pursuant to the prospectus dated April 26, 2021; and

	●	3,657,000 shares of common stock which may be issued upon exercise of the warrants issued in connection with the offering pursuant to the prospectus dated April 26, 2021.

	●	our Annual Report on Form 10-K for the fiscal year ended December 31, 2020, filed with the Securities Exchange Commission on March 25, 2021;

	●	our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2021, filed with the Securities Exchange Commission on May 17, 2021;

	●	our Current Report on Form 8-K, filed with the Securities Exchange Commission on April 26, 2021;

	●	the description of our common stock set forth on Form 8-A12B filed with the Securities Exchange Commission on April 26, 2021, including any amendment or report filed for the purpose of updating such description.

	●	prior to the time of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;

	●	upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the number of shares outstanding (1) shares owned by persons who are directors and also officers and (2) shares owned by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; and

	●	on or subsequent to the time of the transaction, the business combination is approved by the board and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock which is not owned by the interested stockholder.

	●	all of the outstanding shares of the preferred stock deposited with the preferred stock depositary have been withdrawn, redeemed, converted or exchanged; or

	●	there has been a final distribution in respect of the deposited preferred stock in connection with our liquidation, dissolution or winding up and the distribution has been made to the holders of the related depositary shares evidenced by depositary receipts.

	●	the title of the series of debt securities;

	●	any limit upon the aggregate principal amount that may be issued;

	●	the maturity date or dates;

	●	the form of the debt securities of the series;

	●	the applicability of any guarantees;

	●	whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

	●	whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;

	●	if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;

	●	the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

	●	our right, if any, to defer payment of interest and the maximum length of any such deferral period;

	●	if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

	●	the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

	●	the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

	●	any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

	●	whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;

	●	if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders’ option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;

	●	if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;

	●	additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;

	●	additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;

	●	additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;

	●	additions to or changes in the provisions relating to satisfaction and discharge of the indenture;

	●	additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;

	●	the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;

	●	whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;

	●	the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any, and principal amounts of the debt securities of the series to any holder that is not a “United States person” for federal tax purposes;

	●	any restrictions on transfer, sale or assignment of the debt securities of the series; and

	●	any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.

	●	if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;

	●	if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;

	●	if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

	●	if specified events of bankruptcy, insolvency or reorganization occur.

	●	the direction so given by the holder is not in conflict with any law or the applicable indenture; and

	●	subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

	●	the holder has given written notice to the trustee of a continuing event of default with respect to that series;

	●	the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request;

	●	such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and

	●	the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

	●	to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;

	●	to comply with the provisions described above under “Description of Debt Securities-Consolidation, Merger or Sale;”

	●	to provide for uncertificated debt securities in addition to or in place of certificated debt securities;

	●	to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;

	●	to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

	●	to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;

	●	to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided above under “Description of Debt Securities-General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

	●	to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or

	●	to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.

	●	extending the fixed maturity of any debt securities of any series;

	●	reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or

	●	reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

	●	provide for payment;

	●	register the transfer or exchange of debt securities of the series;

	●	replace stolen, lost or mutilated debt securities of the series;

	●	pay principal of and premium and interest on any debt securities of the series;

	●	maintain paying agencies;

	●	hold monies for payment in trust;

	●	recover excess money held by the trustee;

	●	compensate and indemnify the trustee; and

	●	appoint any successor trustee.

	●	the record date for stockholders entitled to receive the rights;
	●	the number of shares of common stock or other securities that may be purchased upon exercise of each right;
	●	the exercise price of the rights;
	●	the terms for changes to or adjustments in the exercise price, if any;
	●	whether the rights are transferable;
	●	the period during which the rights may be exercised and when they will expire;
	●	the steps required to exercise the rights;
	●	whether the rights include “oversubscription rights” so that the holder may purchase more securities if other holders do not purchase their full allotments;
	●	whether we intend to sell the shares of common stock or other securities that are not purchased in the rights offering to an underwriter or other purchaser under a contractual “standby” commitment or other arrangement;
	●	our ability to withdraw or terminate the rights offering;
	●	any material United States federal income tax consequences; and
	●	other material terms, including terms relating to transferability, exchange, exercise or amendment of the rights.

	●	the title of such securities;

	●	the offering price or prices and aggregate number of warrants offered;

	●	the currency or currencies for which the warrants may be purchased;

	●	if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

	●	if applicable, the date on and after which the warrants and the related securities will be separately transferable;

	●	if applicable, the minimum or maximum amount of such warrants which may be exercised at any one time;

	●	in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at which, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

	●	in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which, and the currency in which, these shares may be purchased upon such exercise;

	●	the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

	●	the terms of any rights to redeem or call the warrants;

	●	the terms of any rights to force the exercise of the warrants;

	●	any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

	●	the dates on which the right to exercise the warrants will commence and expire;

	●	the manner in which the warrant agreements and warrants may be modified;

	●	a discussion of any material or special U.S. federal income tax consequences of holding or exercising the warrants;

	●	the terms of the securities issuable upon exercise of the warrants; and

	●	any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

	●	Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

	●	in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

	●	in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

	●	the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

	●	any unit agreement under which the units will be issued;

	●	any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units; and

	●	whether the units will be issued in fully registered or global form.

	●	the name or names of any underwriters, if, and if required, any dealers or agents;

	●	the purchase price of the securities and the proceeds we will receive from the sale;

	●	any underwriting discounts and other items constituting underwriters’ compensation;

	●	any discounts or concessions allowed or re-allowed or paid to dealers; and

	●	any securities exchange or market on which the securities may be listed or traded.

	●	a fixed price or prices, which may be changed;

	●	market prices prevailing at the time of sale;

	●	prices related to such prevailing market prices; or

	●	negotiated prices.

	●	the purchase price of the securities from us;
	●	the net proceeds to us from the sale of the securities;
	●	any delayed delivery arrangements;
	●	any over-allotment or other options under which underwriters, if any, may purchase additional securities from us;
	●	any underwriting discounts, commissions or other items constituting underwriters’ compensation, and any commissions paid to agents;
	●	in a subscription rights offering, whether we have engaged dealer-managers to facilitate the offering or subscription, including their name or names and compensation;
	●	any public offering price; and
	●	other facts material to the transaction.

B. Riley Securities	EF Hutton,
	division of Benchmark Investments, LLC