Thymosin Beta-4
Thymosin beta-4 (Tβ4), marketed in research under the abbreviation TB-500, is a 43-amino acid peptide widely distributed in all animal tissues and representing one of the most abundant intracellular peptides (concentrations reaching 0.1 to 0.5 mM in certain cell types). Originally isolated from bovine thymus in the 1960s by Goldstein, it was long classified in the "thymosin" family before its actual molecular mechanism was elucidated.
The main cellular function of thymosin beta-4 is sequestration of G-actin, the monomeric and soluble form of actin. Each Tβ4 molecule binds one G-actin molecule with 1:1 stoichiometry and prevents its polymerization into filamentous F-actin. This mechanism positions Tβ4 as an essential regulator of cytoskeleton dynamics: by controlling the availability of the free G-actin pool, it influences cell migration, phagocytosis, cytokinesis and rapid cytoskeletal reorganization processes during external stimulations.
Beyond its role on actin, thymosin beta-4 exerts pleiotropic biological effects studied since the 2000s. It promotes angiogenesis by stimulating endothelial cell migration and inducing VEGF. It accelerates epithelial repair through keratinocyte migration promotion and extracellular matrix deposition. It modulates inflammatory response by reducing pro-inflammatory cytokines and favoring macrophage polarization toward the anti-inflammatory M2 phenotype. It stimulates differentiation of cardiac progenitor cells and mesenchymal stem cells.
In exploratory research, thymosin beta-4 generates significant interest for several experimental applications. Tissue regeneration post-myocardial infarction has been the subject of encouraging animal studies suggesting reduction of infarct area and improvement in cardiac function. Corneal and cutaneous healing was investigated in chronic wound models. Tendon and cartilage repair, areas where limited angiogenesis hinders spontaneous healing, represents an axis explored by numerous preclinical teams.
On lab-peptides-france.com, thymosin beta-4 (TB-500) is offered in lyophilized form for research use (RUO, Research Use Only). It is one of the range's flagship peptides, in 5 mg and 10 mg vials; the certificate of analysis is published on the 10 mg page. Its use on humans outside authorized clinical trials is strictly prohibited; it is intended exclusively for laboratories exploring actin cell biology and tissue regeneration mechanisms.