(Exact name of registrant as specified in its charter) FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 SHUTTLE PHARMACEUTICALS HOLDINGS, INC. As filed with the Securities and Exchange Commission on November 18, 2025 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 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 offi ...