As filed with the Securities and Exchange Commission on November 7, 2023. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 FibroBiologics, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) (Primary Standard Industrial Classification Code Number) Delaware 2834 86-3329066 (I.R.S. Employer Identification Number) 455 E. Medical Cen ...