MOLECULAR INFORMATION
Molecular information
- Type
- Synthetic fragment of thymosin beta-4 · purported actin-binding, angiogenic, regenerative
TB-500 is a synthetic fragment (typically the LKKTETQ active region) of the endogenous protein thymosin beta-4. Heavily marketed in equine and human sports recovery for tendon, ligament and muscle injury. The full-length thymosin beta-4 (Tβ4) has been studied clinically; the truncated TB-500 sold grey-market has not.
Claims vs evidence
- Tendon / ligament repair — preclinical animal models only
- Equine performance and recovery — heavily promoted; banned by FEI
- Wound healing — full-length Tβ4 Phase 2 trials exist; TB-500 has none
Why we grade it D
No regulatory authorisation, no completed human RCT, and no sponsor pursuing authorisation. The clinical literature attaches to full-length Tβ4, not the truncated fragment sold in the grey market. Banned across regulated sport. WADA prohibited list inclusion.