TB-500 is a synthetic version of the naturally occurring peptide present in virtually all human and animal cells, Thymosin Beta-4. This potent peptide is a member of a ubiquitous family of 16 related molecules with a high conservation of sequence and localization in most tissues and circulating cells in the body. TB-500 not only binds to actin, but also blocks actin polymerization and is the actin-sequestering molecule in eukaryotic cells.
TB-500 was identified as a gene that was up-regulated four-to-six fold during early blood vessel formation and found to promote the growth of new blood cells from the existing vessels. This peptide is present in wound fluid and when administered subcutaneously, it promotes wound healing, muscle building and speeds up recovery time of muscles fibres and their cells. An additional key factor of TB-500 is that it promotes cell migration through a specific interaction with actin in the cell cytoskeleton. It has been demonstrated that a central small amino acid long-actin binding domain has both blood cell reproduction and wound healing characteristics. These characteristics are uncovered by accelerating the migration of endothelial cells and keratinocytes. It also increases the production of extracellular matrix-degrading enzymes.