Company: SHPH
Filing Date: 2025-12-11
Form Type: S-1/A
Source: 0001493152-25-027310
Chunk: 0

Company: Shuttle Pharmaceuticals Holdings, Inc.
Filing Date: 2025-12-11
Form: S-1/A
Chunk 0
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<div align='center'>As filed with the Securities and Exchange Commission on December 11, 2025</div>

Registration No. 333-291628

<div align='center'>UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

(Amendment No. 1)

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933</div>

| SHUTTLE                                         
 PHARMACEUTICALS HOLDINGS, INC.                  |
| (Exact                                          
 name of registrant as specified in its charter) |

| Delaware                 |     |                2834 |     | 82-5089826     |
| (State                   
 or other jurisdiction of 
 incorporation            
 or organization)         |     |            -Primary 
 Standard Industrial 
      Classification 
         Code Number |     | -I.R.S.        
 Employer       
 Identification 
 No.            |

<div align='center'>401 Professional Drive, Suite 260

Gaithersburg, MD 20879 (240) 430-4212

(Address, including zip code, and telephone number,

including area code, of registrant’s principal executive offices)

Christopher Cooper

Interim Chief Executive Officer

Shuttle Pharmaceuticals Holdings, Inc.

401 Professional Drive, Suite 260

Gaithersburg, MD 20879 (240) 430-4212

(Name, address, including zip code, and telephone number,

including area code, of agent for service)

Copies to:

David E. Danovitch, Esq.
Aaron M. Schleicher, Esq.
Sullivan & Worcester LLP
1251 Avenue of the Americas, 19 thFloor
New York, NY 10020
(212) 660-3060

From time to time after this registration statement becomes effective.

(Approximate date of commencement of proposed sale to the public)</div>

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933 check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box