TB-500 FRAG

A large 100 mg vial of the same 7-amino-acid thymosin beta-4 fragment as the catalog's TB-500. 'FRAG' does not mean a different or more active fragment; TB-500 is already a fragment.

Same proposed mechanism as TB-500: residues 17–23 are the conserved actin-binding motif of thymosin beta-4, a protein that supports cell migration, blood-vessel growth and wound repair in animals. It is not Ac-SDKP (the 1–4 fragment), so the antifibrotic effects linked to that piece are not expected.

No human studies of this molecule exist; FDA found no clinical studies, human PK/PD data or case reports. Full-length thymosin beta-4 (RGN-259) has been tested in human eye-drop trials, including phase 3 dry-eye trials, but those results do not apply to this fragment. In animals and cells, a non-acetylated version aided wound healing in aged mice, TB-500 did not significantly speed fibroblast wound closure, and blood levels in horses were very low. It is studied in wound-healing and tissue-repair models. All human safety data and toxicology are missing.

Human safety is unknown. FDA cites immune-reaction and aggregation risk with research-grade peptides and incomplete quality data on reviewed certificates. For this product no lot-specific purity, identity or endotoxin result is published.

Not FDA-approved. Same compounding history as TB-500: on Category 2 from 2023 and removed in April 2026; in July 2026 FDA's Pharmacy Compounding Advisory Committee voted 8–6–1 to recommend adding TB-500 to the 503A bulks list (for wound healing). The vote is advisory, FDA had issued no final rule as of October 2026, and it concerns pharmacy compounding for patients, not research-grade material. WADA prohibits it at all times (S2).