TB-500

TB-500 is the name the market and the FDA use for a short synthetic fragment of thymosin beta-4: the seven-amino-acid, N-acetylated actin-binding sequence Ac-LKKTETQ (residues 17 to 23). Thymosin beta-4 itself is a 43-amino-acid peptide (about 4963 Da acetylated) and one of the most abundant intracellular actin-sequestering molecules in mammalian cells. The two are not the same molecule. Analytical work on internet-sold TB-500 found products that did not match their descriptions (PMID: 36482504), and a 2024 metabolite study states that the biological effects of the acetylated TB-500 fragment have not been documented (PMID: 38382158). The sequence and mass on a lot certificate of analysis are the only way to know which form a vial holds.

The foundational review by Goldstein et al. (2005) established full-length thymosin beta-4 as a multifunctional regenerative peptide with roles spanning wound healing, angiogenesis, anti-inflammation, and cardiac repair. Unlike many bioactive peptides, thymosin beta-4 is not a hormone or cytokine but rather an intracellular actin-regulatory protein that, when released extracellularly following injury, initiates paracrine signaling cascades that drive tissue repair. Most of what follows is full-length thymosin beta-4 data; the fragment's efficacy data appears only in the wound-healing paragraph.

Thymosin beta-4 has been studied extensively in preclinical models of cardiac injury. Bock-Marquette et al. (2004) demonstrated that thymosin beta-4 promotes survival of cardiomyocytes after experimental myocardial infarction in mice, reduces infarct size, and improves cardiac function. The mechanism involves activation of the Akt (protein kinase B) survival pathway and migration of cardiomyocytes and endothelial cells toward the injury. These findings positioned thymosin beta-4 as a candidate cardiac repair agent, though clinical translation has been limited.

In wound healing research, thymosin beta-4 accelerates dermal wound closure by promoting keratinocyte and endothelial cell migration, increasing angiogenesis, and reducing inflammation at the wound site. Philp et al. (2003) showed that topical thymosin beta-4 significantly accelerated full-thickness wound closure in diabetic and aged mouse models, and in the same paper the free seven-residue fragment LKKTETQ promoted repair in aged animals comparable to the parent peptide (PMID: 12581423). That one mouse study, plus in-vitro assays, is the fragment record; there is no human data for the fragment.

Thymosin beta-4 has also shown efficacy in corneal wound healing models. Sosne et al. demonstrated that thymosin beta-4 eye drops accelerate corneal epithelial wound closure and reduce inflammation after chemical or mechanical injury, leading to ophthalmic clinical trials (Phase 2 and Phase 3, RGN-259) for dry eye and neurotrophic keratopathy. This is the most advanced clinical development program for any thymosin beta-4-based therapeutic, and it is topical.

TB-500 is not FDA-approved for any human therapeutic indication. It is a doping-control target in racing horses (PMID: 23084823) and is used in the human peptide biohacking community for musculoskeletal recovery, wound healing, and anti-inflammatory effects, on the strength of the full-length peptide literature rather than any human fragment data.

TB-500 is available in vial form.

Compare prices, payment methods, shipping, and COA scores across 4 vendors.

4 of the vendors BodyHackGuide tracks list TB-500 (8 listings). Among BodyHackGuide's TB-500 listings recorded as in stock with a milligram count, the lowest price per milligram is $4.90/mg at Ion Peptide and the median is $6.40/mg. The TB-500 prices on BodyHackGuide are vendors' listed prices as BodyHackGuide last recorded them, not transactions; the most recent recorded change to a TB-500 listing is dated 8 October 2026.

BodyHackGuide holds 125 third-party certificate records for TB-500, from ResearchChemHQ and Half Nattys. An editor has read 1 of BodyHackGuide's 125 certificate records for TB-500 and recorded the laboratory, the compound and the test date as printed on each. The laboratories named on BodyHackGuide's TB-500 certificate records are Janoshik Analytical and Freedom Diagnostics Testing, and the newest test date on them is 6 October 2026. Each vendor page on BodyHackGuide shows how many certificate records BodyHackGuide holds for that vendor and links to each record that has its own page.