United States securities and exchange commission logo August 18, 2021 Alexander K. Arrow Chief Financial Officer Protagenic Therapeutics, Inc.\new 149 Fifth Avenue New York, New York 10010 Re: Protagenic Therapeutics, Inc.\new Registration Statement on Form S-3 Filed August 13, 2021 File No. 333-258825 Dear Dr. Arrow: This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Jacqueline Kaufman at 202-551-3797 with any questions. Sincerely, Division of Corporation Finance Office of Trade & Services cc: Dean Colucci