BPC-157 vs TB-500: origin, mechanism and evidence
Updated: October 8, 2026
They are two peptides studied in tissue repair models that appear together in the KLOW blend. They have different origins and mechanisms and also a different level of evidence.
Origin
- BPC-157: a synthetic 15-amino-acid fragment derived from a protective protein of gastric juice.
- TB-500: a synthetic fragment of thymosin β4, a 43-amino-acid actin-sequestering protein; the fragment corresponds to its actin-binding region.
Studied mechanism
- BPC-157: in rodents, actions on angiogenesis, nitric oxide and growth factors have been described.
- Thymosin β4: involved in cell migration and repair through actin cytoskeleton dynamics.
State of the evidence
Most BPC-157 studies come from a single research group and human data are very scarce. Clinical trials with thymosin β4 were done with the full-length protein and not with the TB-500 fragment. Both are on the World Anti-Doping Agency prohibited list.