TB-500

TB-500 is a synthetic peptide based on the active region of Thymosin Beta-4, a naturally occurring 43-amino-acid protein found in virtually all human and animal cells. The active fragment corresponds to the actin-binding domain of Thymosin Beta-4 and is responsible for many of the protein's regenerative properties. TB-500 promotes cell migration, angiogenesis, and the differentiation of stem cells, making it a compound of significant interest for tissue repair and recovery.

Research in animal models has shown that TB-500 and its parent protein Thymosin Beta-4 can accelerate wound healing, reduce inflammation, promote hair regrowth, and even support cardiac tissue repair following ischemic events. The peptide works by upregulating actin, which is critical for cell structure and motility. This enables cells to migrate more effectively to sites of injury and participate in the repair process. Studies have also demonstrated benefits in corneal healing, reducing scarring, and protecting against fibrosis.

TB-500 is widely used in the athletic and equine performance communities, though it should be noted that it is prohibited by WADA and most equine racing authorities. Like many peptides in the recovery category, human clinical trial data remains limited, and most of the evidence base comes from preclinical animal studies.

Thymosin Beta-4 was originally isolated from the thymus gland by Allan Goldstein's research group at George Washington University in the 1960s-1970s as part of thymosin fraction 5, a mixture of small proteins with immunomodulatory properties. The specific 43-amino-acid protein was sequenced in 1981, revealing its role as a major actin-sequestering protein in mammalian cells. TB-500 is a synthetic fragment corresponding to the active actin-binding domain (amino acids 17-23) of Thymosin Beta-4.

RegeneRx Biopharmaceuticals developed Thymosin Beta-4 for clinical applications, pursuing investigations in wound healing, corneal repair, and cardiac recovery. The peptide was extensively studied in equine medicine for racehorse recovery from tendon and ligament injuries, where it gained a reputation for accelerating return-to-performance timelines. This widespread use in horse racing became controversial, and in 2010 the World Anti-Doping Agency (WADA) added Thymosin Beta-4 to its prohibited substances list, reflecting concerns about its performance-enhancing potential in both equine and human athletics.