Company: NCEL
Filing Date: 2025-09-19
Form Type: 6-K
Source: 0001213900-25-089523
Chunk: 0

Company: NewcelX Ltd.
Filing Date: 2025-09-19
Form: 6-K
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<div align='center'>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 September 2025 (Report No. 3)

Commission file number: 001-39957

NLS PHARMACEUTICS LTD.

(Translation of registrant’s name into English)

The Circle 6,

CH-8058 Zurich, Switzerland

(Address of principal executive offices)</div>

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

<div align='center'>Form 20-F ☒
Form 40-F ☐

CONTENTS</div>

On
November 1, 2024, CBIZ CPAs P.C. (“CBIZ”) acquired the attestation business of Marcum LLP (“Marcum”). As a result
of the acquisition of the Marcum attestation business, on September 17, 2025, NLS Pharmaceutics Ltd. (the “Company”)
was notified by Marcum, that Marcum will resign effective immediately. Concurrently with the Marcum notification, on September 17,
2025, the Company entered into an engagement letter with CBIZ to appoint CBIZ as the Company’s independent registered public accounting
firm, and on September 17, 2025, the Company, with the approval of the Audit Committee of the Company’s Board of Directors, engaged
CBIZ as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2025.

The report of Marcum on the
financial statements for the fiscal year ended December 31, 2024 contained no adverse opinion or disclaimer of opinion and was not qualified
or modified as to uncertainty, audit scope or accounting principle except that the report of Marcum on the Company’s consolidated
financial statements for the fiscal year ended December 31, 2024 contained an explanatory paragraph regarding substantial doubt about
the Company’s ability to continue as a going concern.

During the fiscal year ended
December 31, 2024 and the subsequent interim period through September 17, 2025, there were (i) no “disagreements” (as that
term is defined in Item 304(a)(1)(iv)