Side by side, from official and peer-reviewed sources
| Item | BPC-157 | TB-500 |
|---|---|---|
| What it is | A peptide reported to have 15 amino acids [1] | A synthetic 7-amino-acid fragment of thymosin beta-4 (Ac-LKKTETQ); FDA notes it is not the same substance as thymosin beta-4 [2] |
| Approved product | None: not part of any FDA-approved drug; FDA says no approved product exists in any country [1] | None: not part of any FDA-approved drug; no EU-authorised product [2] |
| Official dose or schedule | None (no label) | None (no label) |
| Published human data | Very limited: one clinical study among 36 in a 2025 review [5]; three small studies (30 people) in a 2026 review rated very low certainty [6] | FDA found no human studies or human exposure data for TB-500 itself [2] |
| FDA compounding status | Was on FDA’s significant-safety-risk list from 2023; nomination later withdrawn [3]. FDA staff advised in 2026 against adding it to the 503A bulks list [1] | Same history [3]; FDA staff advised in 2026 against adding it to the 503A bulks list [2] |
| Sport (WADA) | Prohibited at all times (S0, named) [7] | Prohibited at all times (S2, “thymosin-β4 and its derivatives e.g. TB-500”) [7] |
Thymosin beta-4 is not TB-500
Studies sometimes cited for TB-500, such as eye drops or intravenous trials, used full-length thymosin beta-4. FDA’s briefing document states the two are not the same substance, so those results do not describe TB-500 [2].
About the July 2026 advisory committee
FDA staff recommended that neither peptide be added to the list of substances pharmacies may compound [1][2]. The advisory committee voted differently; its votes are advice to FDA and do not change the list [4]. When this page was checked, neither substance was on it.
