TB-500, 2mg/vial Thymosin β4 Acetate (TB-500) Standard Size 200 µg Sequence Ac - ... ≥95% TB-500 is a synthetic fraction of the protein thymosin beta-4, which is present in virtually all human and ... observed in tendons, ligaments, muscle, skin, heart, and the eyes. Thymosin beta-4 is naturally produced in higher concentration where tissue ...