A synthetic peptide derived from the active region of thymosin beta-4, a natural protein involved in cell migration and repair.
Thymosin beta-4 is a 43-amino-acid protein present in most human cells, where it binds actin and helps cells move during repair. TB-500 is a synthetic peptide modeled on part of that protein. The two are often used interchangeably online, but they are not the same molecule, and research on one does not automatically apply to the other.
TB-500 followed the same path as BPC-157: placed in FDA's 503A Category 2 in 2023, removed effective April 23, 2026, and recommended for the 503A bulks list by the Pharmacy Compounding Advisory Committee on July 23, 2026 by an 8–6 vote with one abstention, against the recommendation of FDA staff. The vote is non-binding, and TB-500 is not an FDA-approved drug.
Status reflects public FDA actions and reporting as of October 8, 2026. An advisory committee vote is a recommendation, not an FDA decision, and inclusion on a compounding list is not FDA approval.
Animal studies of thymosin beta-4 report effects on wound, heart and eye repair. The full protein has been tested in human trials, including as eye drops for corneal conditions, without leading to an approved product. Controlled human evidence for TB-500 itself is essentially absent.
nnng.com does not publish doses, cycles or protocols for peptides. For approved drugs, the dose comes from the FDA-approved prescribing information and your prescriber. For unapproved compounds there is no established human dose, and numbers that circulate online are usually extrapolated from animal studies or written by sellers. If a clinician has already prescribed a dose, our reconstitution calculator converts that prescribed amount into syringe units. It is arithmetic only and does not suggest a dose.