BPC-157 vs TB-500: structure, research and legal status compared
BPC-157 and TB-500 are the two peptides most often discussed together in tissue-repair research, and they are frequently confused. They come from different parent proteins, have different structures and have been studied through different proposed mechanisms. This page compares them side by side for laboratory and educational purposes.
- BPC-157 is a 15-amino-acid fragment of a protein found in gastric juice.
- TB-500 is a synthetic 7-amino-acid fragment of thymosin β4, a 43-amino-acid actin-binding protein.
- Neither is FDA-approved. In July 2026 an FDA advisory committee recommended both for the 503A bulks list; the vote is not binding (details).
- Both are banned by WADA.
Side-by-side comparison
| BPC-157 | TB-500 | |
|---|---|---|
| Full name | Body Protection Compound-157 | Thymosin β4 fragment (often sold as "TB-500") |
| Parent protein | A protein in human gastric juice | Thymosin β4 (43 amino acids) |
| Length | 15 amino acids | 7 amino acids |
| Sequence | GEPPPGKPADDAGLV | Ac-LKKTETQ |
| Molecular weight | 1419.53 g/mol | ≈889 g/mol |
| Formula | C₆₂H₉₈N₁₆O₂₂ | C₃₈H₆₈N₁₀O₁₄ |
| CAS number | 137525-51-0 | Varies by supplier; check the COA |
| Main research areas | Tissue-repair and gastrointestinal models in animals | Tissue-repair and cell-migration models |
| Proposed mechanism | Angiogenesis, nitric-oxide and growth-factor signalling (proposed, mainly from animal work) | Actin binding and cell migration, based on the thymosin β4 region it copies |
| Human clinical data | Very limited; no published human pharmacokinetic study | Very limited for the fragment itself |
| US status | Not FDA-approved; recommended by an FDA advisory committee in July 2026 | Not FDA-approved; recommended by an FDA advisory committee in July 2026 |
| UK / EU status | Unlicensed; research use only | Unlicensed; research use only |
| WADA | Prohibited (S0) | Prohibited (thymosin β4 and derivatives) |
How their structures differ
BPC-157 is a linear 15-residue peptide rich in proline and with a free N-terminus. TB-500 is much shorter and is usually N-acetylated. Because both are often sold as acetate salts, the weighed mass of a vial is higher than the free-peptide figure; use the molecular weight on your certificate of analysis for calculations in our lab calculator.
How their research differs
Most BPC-157 literature comes from animal models of gut, tendon, muscle and vascular injury, much of it from a small number of research groups. TB-500 research draws on the wider thymosin β4 literature, which is linked to actin regulation and cell migration, but fewer studies test the 7-residue fragment itself. For both, the human evidence base is thin, so claims of proven effects in people are not supported.
Buying either for a lab
Check the sequence, molecular weight, purity (HPLC) and mass-spectrometry identity on a batch-specific certificate of analysis. TB-500 in particular is sometimes mislabelled as full-length thymosin β4. See the supplier checklist on each profile: BPC-157 and TB-500.
Frequently asked questions
Is BPC-157 the same as TB-500?
No. BPC-157 is a 15-amino-acid fragment of a gastric protein. TB-500 is a 7-amino-acid fragment of thymosin β4. They are different molecules.
Which is better, BPC-157 or TB-500?
There is no reliable human evidence to rank them. They have been studied in different models through different proposed mechanisms, and neither is approved for human use.
Are BPC-157 and TB-500 legal in the US?
Neither is FDA-approved. Both were recommended for the 503A bulks list by an FDA advisory committee in July 2026, but the vote is not binding and no rule had been proposed as of 27 October 2026.
Are BPC-157 and TB-500 banned in sport?
Yes. WADA prohibits BPC-157 as a non-approved substance and names thymosin β4 and its derivatives, including TB-500, on its Prohibited List.
Is TB-500 the same as thymosin beta-4?
No. TB-500 is a short synthetic fragment based on part of thymosin β4, not the full 43-amino-acid protein.