Exhibit 16.1

January 12, 2024

Securities and Exchange Commission

100 F Street, NE

Washington, DC 20549

Dear Ladies and Gentlemen:

We are the former independent registered public accounting firm for Arch Therapeutics, Inc. (the “Company”). We have read the Company’s disclosure set forth in Item 4.01 “Changes in Registrant’s Certifying Accountant” of the Company’s Current Report on Form 8-K dated January 12, 2024 (the “Current Report”) and are in agreement with the disclosure in the Current Report, insofar as it pertains to our firm.

Sincerely,

/s/ Baker Tilly US, LLP