TB-500

TB-500 is marketed as a synthetic version of a fragment of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid peptide present in nearly all human and animal cells. Tβ4's best-documented action is binding monomeric G-actin, sequestering it and regulating its polymerization into filamentous (F-) actin — a process central to cell migration and motility. In preclinical models this actin-regulating activity is linked to downstream effects such as promotion of endothelial cell migration and angiogenesis, mobilization of progenitor/stem-like cells toward injured tissue, and modulation of local inflammatory signaling. Most of this mechanistic work has been done with full-length Tβ4 (or the RGN-137 topical formulation), not with the shorter 'TB-500' fragment sold online, so mechanistic extrapolation from Tβ4 to TB-500 is not fully established.

Evidence is preclinical evidence for the most part: rodent and other animal wound, tendon, muscle, and cardiac-injury models show accelerated re-epithelialization, reduced fibrosis/scarring, and increased vascularization with Tβ4 administration. Human evidence is limited and specific to full-length Tβ4 formulations, not TB-500: a small number of completed or terminated Phase 2 trials of the topical RGN-137 formulation were run in pressure ulcers, venous stasis ulcers, and epidermolysis bullosa, with mixed or inconclusive results and no approved product resulting. No human clinical trials of the injectable fragment marketed as 'TB-500' have been published. It is not an approved drug anywhere and is not intended for human use outside of research.

Educational overview only — no dosing instructions in the public hub.

Long-term human safety data do not exist for the injectable fragment sold as TB-500. Reported concerns in user and preclinical literature include theoretical pro-angiogenic effects that could, in principle, support unwanted vascular growth (including in existing tumors), injection-site reactions, and unknown immunogenicity from unregulated peptide synthesis (purity/endotoxin risk). It is classified as a prohibited substance under WADA's S2 category for competitive athletes. Products sold as 'TB-500' are unregulated research chemicals, not verified pharmaceuticals.

Because 'TB-500' is not an approved drug, sourcing quality varies widely. Look for an independent third-party Certificate of Analysis (CoA) from an accredited lab covering identity/purity by HPLC, quantification (actual peptide content vs. label claim), and mass spectrometry (MS) confirmation of molecular identity — not just a manufacturer-supplied CoA.

Not approved by the FDA, EMA, or any other medicines regulator for human use. Sold in most jurisdictions labeled 'Research Use Only (RUO), not for human consumption.' Prohibited at all times for competitive athletes under WADA's S2 (Peptide Hormones, Growth Factors and Related Substances) category.