TB-500: Dosage, Benefits, FDA Status & Clinics (2026)
What Is TB-500? TB-500 is a synthetic fragment of thymosin beta-4 — a naturally occurring protein found in virtually every human cell — and it's the piece of that protein that does most of the heavy lifting when it comes to tissue repair. Specifically, it's th
What Is TB-500?
TB-500 is a synthetic fragment of thymosin beta-4 — a naturally occurring protein found in virtually every human cell — and it's the piece of that protein that does most of the heavy lifting when it comes to tissue repair. Specifically, it's the heptapeptide LKKTETQ (amino acids 17 through 23), the actin-binding region that drives cell migration, wound healing, and new blood vessel formation.[1] The full thymosin beta-4 protein has 43 amino acids; TB-500 is a stripped-down version built around the sequence that matters most for recovery.
What makes TB-500 interesting to athletes, injury patients, and researchers is the breadth of what thymosin beta-4 signaling does downstream: angiogenesis, collagen deposition, fibroblast activation, and inflammation control — all processes that determine how fast and how completely tissue heals.[2] The synthetic fragment was originally developed as a veterinary product and has been flagged as a doping substance in equine sports, which tells you something about how seriously the performance world takes it.[1]
Here's the honest reality: the human clinical evidence is thin. Most of the data comes from animal models. TB-500 is not FDA-approved, not available through US compounding pharmacies under current guidance, and is used primarily in research settings or through gray-market channels. If you're reading this page trying to decide whether to use it, the evidence base matters — and you deserve a straight account of what it actually shows.