TB-500
TB-500 is studied for its role in actin regulation and cell migration, mechanisms relevant to tissue repair research. It is one of the most widely referenced peptides in recovery-focused literature.
Part of KYIN Peptides' standard catalogue — see the product page for pricing.
What Is TB-500?
TB-500 is a synthetic fragment of a much older discovery: thymosin beta-4, a 43-amino-acid peptide first isolated from bovine thymus tissue in 1981 by Teresa Low and Allan Goldstein as part of NIH-funded research. At the time, thymosin beta-4 was studied primarily as an immunological molecule, in keeping with the thymus's role in immune function. That understanding changed roughly a decade later: in the early 1990s, work by Safer, Bhaskara, Sanders, Goldstein, and Wang identified thymosin beta-4 as a major G-actin-sequestering molecule — meaning it binds and regulates the building blocks of the cell's actin cytoskeleton. That finding reframed the entire molecule, shifting it from an immune signal to a cytoskeletal regulator relevant to cell movement and tissue repair. See its full discovery history.
Research Focus
TB-500's research applications follow directly from thymosin beta-4's actin-regulating mechanism, and it remains one of the most frequently referenced peptides in tissue-repair research literature. It sits in KYIN's Healing & Recovery category alongside BPC-157, GHK-Cu, and KPV, and is combined with BPC-157 in our TB-500 + BPC-157 Blend. See our Healing & Recovery research overview, or how it compares to BPC-157, KPV, and GHK-Cu.
- Tissue repair and regeneration research
- Cell migration studies
- Actin-binding mechanism research
Clinical & Preclinical Trial Data
It's important to distinguish TB-500 (the shorter synthetic fragment sold commercially) from full-length Thymosin Beta-4, which is what RegeneRx Biopharmaceuticals actually studied in human trials — the two are related but not identical molecules. RegeneRx's Thymosin Beta-4 trials include: RGN-352 (injectable), a Phase I trial in 40 healthy volunteers that was well tolerated with no adverse events, though a later Phase II cardiovascular trial was placed on a manufacturing-related FDA clinical hold; RGN-137 (topical gel), a Phase II venous stasis ulcer trial showing faster but not statistically significant healing versus placebo; and RGN-259 (ophthalmic), a Phase III trial for neurotrophic keratopathy that met its endpoints for improved healing and comfort. None of this trial data is for TB-500 specifically as sold for research use.
In July 2026, an FDA advisory committee recommended TB-500 for the 503A compounding bulks list — a non-binding vote, not FDA drug approval. Read what it actually means →
Availability
TB-500 is part of KYIN Peptides' standard catalogue — see the product page for pricing, or contact us to order.
TB-500 questions
What is TB-500?
TB-500 is a synthetic fragment of thymosin beta-4, a 43-amino-acid peptide first isolated from bovine thymus tissue in 1981. TB-500 is studied for its role in actin regulation and cell migration — mechanisms relevant to tissue repair research.
Has TB-500 been tested in human trials?
Not TB-500 itself. RegeneRx Biopharmaceuticals has studied full-length Thymosin Beta-4 in human trials under names like RGN-352, RGN-137, and RGN-259, across cardiovascular, dermatological, and ophthalmic indications with mixed results. TB-500, the shorter synthetic fragment sold for research use, is a related but distinct molecule, and none of that trial data applies to it directly.
Does KYIN Peptides sell TB-500?
Yes — TB-500 is part of our standard catalogue, both individually and in our KLOW Blend and TB-500 + BPC-157 Blend. See the product pages for pricing.
Interested in TB-500?
See pricing and order on the product page, or browse our other healing & recovery peptides.