6-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16

under the Securities Exchange Act of 1934

For the month of August 2025

Commission file number: 001-39957

NLS PHARMACEUTICS LTD.

(Translation of registrant’s name into English)

The Circle 6

8058 Zurich, Switzerland

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

CONTENTS

Warrant Exchange Agreement

On August 5, 2025, NLS Pharmaceutics Ltd. (the “Company”) entered into a warrant exchange agreement (the “Exchange Agreement”) with Alpha Capital Anstalt (the “Holder”). Pursuant to the terms of the Exchange Agreement, the Company and the Holder agreed to exchange a certain common share purchase warrant dated October 10, 2024 to purchase 207,913 of the Company’s common shares previously issued to the Holder under a securities purchase agreement dated October 9, 2024, between the Company and certain accredited investors, including the Holder (the “Warrant”), for 100,000 common shares, par value CHF 0.03 of the Company (the “Exchange Shares”).

The Exchange Shares are being issued in reliance on an exemption from registration under Section 3(a)(9) of the Securities Act of 1933, as amended. Pursuant to the Exchange Agreement, the Company agreed to issue the Exchange Shares within one trading day of execution, and acknowledged that the Holder’s holding period for Rule 144 purposes will tack back to the original issue date of the Warrant. The Exchange Shares will have the same rights as the warrant shares under specified provisions of the Warrant.

In addition, the Holder waived any liquidated damages related solely to the Company’s registration obligations under the Securities Purchase Agreements dated October 9, 2024 and December 4, 2024, and the related Registration Rights Agreement, all as previously executed between the Company and the Holder. No other rights under any other agreements were waived.

The foregoing description of the Exchange Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Exchange Agreement, which is filed as Exhibit 99.1 to this Current Report on Form 6-K and incorporated herein by reference

EXHIBIT INDEX

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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Exhibit 99.1

Execution Version

EXCHANGE AGREEMENT

THIS EXCHANGE AGREEMENT (this “Agreement”), dated as of August 5, 2025, is entered into by and between NLS Pharmaceutics Ltd., a corporation incorporated under the laws of Switzerland (the “Company”) and Alpha Capital Anstalt (the “Holder”).

RECITALS

WHEREAS, the Holder is the holder of a warrant dated October 10, 2024, to purchase 207,913 shares of the Company’s common shares (the “Warrant”) to each purchaser;

WHEREAS, the Company and the Holder desire to exchange the Warrant for common shares of the Company.

NOW, THEREFORE, in consideration of the premises and mutual covenants herein, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, hereby agree as follows:

1. Exchange. Pursuant to an exemption from registration under 3(a)(9) of the Securities Act of 1933, as amended (the “Securities Act”), the Company and Holder hereby agree to exchange the Warrant for 100,000 shares of the Company’s Common Shares (the “Exchange Shares”). The Exchange Shares will be issued within one (1) trading day after the date of this Agreement.

2. Tacking. The Company acknowledges that the Holder’s holding period of the Exchange Shares shall tack for Rule 144 purposes back to the issue date of the Warrant. The Holder acknowledges and agrees that the issuance of the Exchange Shares shall not result in the triggering of any anti-dilutive provisions contained in any securities currently owned by the Holder. The Company further agrees that the Exchange Shares shall have all the same rights as Warrant Shares under section 2(d)(i) and 2(d)(iv), 2(d)(vi) of the Warrant.

3. Waiver. The Holder waives any and all liquidated damages arising from the Company’s registration obligations solely relating to all securities issued and sold pursuant to the Securities Purchase Agreements dated October 9, 2024 and December 4, 2024, respectively, and the Registration Rights Agreement dated October 9, 2024, each as executed by and between the Company and the Holder. This shall not waive any rights of Holder under any other agreement.

4. Disclosure. Unless the Company informs the Holder that this agreement is not considered material non-public information, within two (2) business days after execution of this Agreement, the Company shall file a form 6-K with the Securities and Exchange Commission, disclosing this Agreement, which shall be an exhibit to such filing. The form 6-K shall be provided to Holder for review and comment prior to filing.

5. Entire Understanding; No Third-Party Beneficiaries. This Agreement represents the entire understanding of the parties with reference to the transactions contemplated hereby and this Agreement supersedes any and all other oral or written agreements heretofore made with respect to the subject matter hereof. Nothing in this Agreement, expressed or implied, is intended to confer upon any Person, other than the parties, or their respective successors and permitted assigns, any rights, remedies, obligations or liabilities under or by reason of this Agreement.

6. Governing Law. This Agreement shall be governed by, and interpreted in accordance with, the laws of the State of New York applicable to contracts made and to be performed entirely within such State. Each party agrees that all legal proceedings concerning the interpretations, enforcement and defense of the transactions contemplated by this Agreement (whether brought against a party hereto or its respective affiliates, directors, officers, shareholders, partners, members, employees or agents) shall be commenced exclusively in the state and federal courts sitting in the City of New York. Each party hereby irrevocably submits to the exclusive jurisdiction of the state and federal courts sitting in the City of New York, Borough of Manhattan for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein, and hereby irrevocably waives, and agrees not to assert in any action, suit or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is improper or is an inconvenient venue for such proceeding. Each party and each signatory hereto on behalf of the Company, hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof.

7. Purchaser Status. At the time the Holder was offered the Exchange Shares it was either: (i) an accredited investor (“Accredited Investor”) as defined in Rule 501(a)(1), (a)(2), (a)(3), (a)(7) or (a)(8) under the Securities Act or (ii) a “qualified institutional buyer” as defined in Rule 144A(a) under the Securities Act. Such Holder has the authority and is duly and legally qualified to purchase and own the Exchange Shares. Such Holder is able to bear the risk of such investment for an indefinite period and to afford a complete loss thereof.

8. Counterparts. This Amendment may be executed in any number of counterparts, and each such counterpart shall be deemed to be an original instrument, but all such counterparts together shall constitute but one agreement. This Amendment shall become effective when one or more counterparts have been signed by each of the parties hereto and delivered to the other party, it being understood that the parties need not execute the same counterpart. Facsimile signatures or signatures received as a portable document format (PDF) attachment to electronic mail shall be treated as original signatures for all purposes hereunder.

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IN WITNESS WHEREOF, the parties hereto have executed this Amendment as of the date first set forth above.