BPC-157 vs TB-500: Differences, Evidence, Side Effects and Stacking

Short answer: BPC-157 has a little human evidence and TB-500 has none. They are different peptides: BPC-157 is a 15-amino-acid chain based on a stomach protein; TB-500 is a 7-amino-acid fragment of thymosin beta-4, the piece that binds the cell protein actin. Both are sold for injury recovery on the strength of animal and lab studies. The FDA found five small human reports for BPC-157 and no human data at all for TB-500. Neither is approved, both are banned in sport, and the popular blend of the two has never been tested.

BPC-157 vs TB-500 at a glance

Scores run from 0 (none) to 3 (high); see our methodology. Data from the SARMs database.

How they work

BPC-157 is a synthetic 15-amino-acid peptide (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) derived from a protein in gastric juice. In animal and lab studies it sped up healing of tendons and gut and increased blood-vessel growth with raised VEGFR2 signaling, but the FDA notes its molecular target is still unknown.

TB-500 is the acetylated fragment 17–23 of thymosin beta-4 (Ac-LKKTETQ), the part of the protein that binds actin. “TB-500” is a trade name, and the FDA has seen different salts and molecules sold under it; products are often labeled “thymosin beta-4”, which is actually the full 43-amino-acid protein. In lab tests, a breakdown product of TB-500 (Ac-LKKTE), not TB-500 itself, sped up wound closure in fibroblasts; the FDA found no studies showing TB-500 itself promotes wound healing.

What the human evidence shows

Side effects

For BPC-157, the enema studies reported headache and flatulence at placebo-like rates, and the FDA’s adverse event database holds three reports (injection-site swelling, shortness of breath, and skin and gum darkening). For TB-500, the FDA found no clinical studies and no adverse event reports. The one skin-darkening report involved a “research use” product containing both peptides, so which one caused it is unclear. For both, the FDA warns that injected peptides can aggregate or carry impurities that trigger immune reactions, and for TB-500 that buyers may not get the molecule on the label.

Regulatory status

Neither is an approved drug. Both were nominated for US pharmacy compounding and then withdrawn from the FDA’s Category 2 safety-risk list. At the FDA Pharmacy Compounding Advisory Committee on 23 July 2026, members voted 8–6 (1 abstention) to recommend adding BPC-157 for ulcerative colitis and, separately, 8–6 (1 abstention) for TB-500 for wound healing, after FDA staff advised against both. The vote is non-binding; the FDA had not made a final decision as of 30 October 2026. In Australia both are Schedule 4 prescription-only medicines. See our news post on the FDA panel vote.

In sport

WADA bans both at all times, in different sections: BPC-157 under S0 (non-approved substances) and TB-500 under S2.3 (thymosin beta-4 and its derivatives). Anti-doping labs have validated urine tests for BPC-157 and include TB-500 in peptide screening.

BPC-157 and TB-500 together

The blend is popular because the two are thought to work through different routes (blood-vessel growth vs actin binding). No study has tested the combination, and the only human report involving both is the FDA’s skin-darkening case. SwissChems sells each separately and as a BPC-157 + TB-500 blend.

Verdict

If the question is which has more evidence, BPC-157, but “more” means five small reports of very low certainty. TB-500 has no human data, and the strongest results attributed to it come from studies of the full thymosin beta-4 protein, a different molecule. Both are unapproved, banned in sport, and only narrowly backed by an FDA panel for specific medical uses. Read the full BPC-157 review and TB-500 review, and see peptides for healing and recovery.