TB-500

Thymosin Beta-4 fragment (TB4 17-23)

Synthetic fragment of Thymosin Beta-4 used in tissue repair research

FDA Status

Not FDA-approved · Off-WADA list for sport (banned)

Class

Heptapeptide fragment of TMSB4X

Sequence

LKKTETQ

Half-life

~2-3 hours

Mechanism of action

• Actin-binding regulator — promotes cell migration and differentiation
• Anti-inflammatory action via IL-1β suppression
• Stimulates angiogenesis through endothelial cell migration
• Induces hair follicle stem cell activity

Research areas

• Equine soft-tissue injury (most documented application)
• Cardiac muscle repair post-infarct (animal data)
• Corneal wound healing
• Hair regrowth (preliminary research)

Evidence and clinical data

Veterinary use in racehorses is well-documented. Human clinical data is sparse. Most TB-500 references in commercial literature confuse the 7-amino-acid synthetic fragment with full-length Thymosin Beta-4 (43 aa) — the two are pharmacologically different.

Safety profile

Not WADA-approved for athletic use (banned in competition). Limited human toxicology data. Known to remain detectable in blood for weeks post-injection.