Thymosin Beta-4 fragment
A synthetic fragment of the natural healing protein thymosin beta-4 — solid animal evidence, no controlled human data on the injected form, and a firm WADA ban.
✦ 2 min read · 2 sourcesWhat it is
TB-500 is a synthetic 7-amino-acid peptide copying the active actin-binding region of thymosin beta-4 (TΒ4), a protein found in nearly every human cell and released at wound sites. It is a fragment/analog, not the full natural protein, and is not FDA-approved.
How it works
TΒ4 binds G-actin, a building block of the cell's internal scaffolding. By regulating actin, TB-500 is thought to help cells reorganize and migrate to an injury — an early step in healing — with proposed downstream angiogenesis, reduced inflammation, and tissue regeneration.
What the evidence shows
Animal and cell research consistently supports a role for thymosin beta-4 in skin, corneal, cardiac, tendon, and muscle repair, replicated by independent labs. The crucial caveat: the best human data come from full-length TΒ4 in a topical eye-drop, not the injected TB-500 fragment athletes use. There are essentially no rigorous human trials of injected TB-500 for sports injuries.
Quick check
Four questions, ~60 seconds, with a sourced result.
The honest take
Consistent animal data; no injectable human trials; WADA-banned
Status & safety
Not FDA-approved for this use. TB-500 / thymosin beta-4 derivatives are named on the WADA Prohibited List under S2 (peptide hormones, growth factors), banned at all times. Purity is a real concern with research-only suppliers.
Summaries of published, third-party research for educational purposes. Not medical advice; not a claim of efficacy or safety for any use.
New, plain-language summaries as the literature develops. Educational only — no products, nothing for sale.
Body Protection Compound-157
A synthetic peptide with striking tissue-healing effects in animals but essentially no controlled human evidence — FDA-flagged and banned in sport.
Read more →Copper Tripeptide-1
A naturally occurring copper-binding peptide with the strongest human evidence of these three — but mostly for skin and wounds, not athletic tissue recovery.
Read more →