Research brief · 2026-09-09
What Does TB-500 Actually Do? What the Research Shows
TB-500 is usually sold as a recovery peptide for tendon, ligament and muscle injuries. To understand the research, you first have to understand what it is. TB-500 is not something the body makes. It is a synthetic copy of a seven-amino-acid piece cut from a much larger natural protein, thymosin beta-4, which the body does produce. An anti-doping chemistry paper in Drug Testing and Analysis identified the substance sold as TB-500 as an acetylated version of amino acids seventeen through twenty-three of that protein. It is not approved as a medicine anywhere.
That distinction matters because nearly every real human trial quoted under the words thymosin beta-4 used the full-length protein, made by different companies under different names. ClinicalTrials.gov record NCT00382174 was a Phase Two trial of a thymosin beta-4 gel in seventy-two patients with pressure ulcers. NCT03937882, the ARISE-3 trial, tested a thymosin beta-4 eye drop in seven hundred people with dry eye disease. Both posted results. Neither product is TB-500, and neither studied tendon, ligament or muscle injury.
The full-length protein also has a substantial animal literature, with reports of faster skin wound healing in rats and pigs. The short fragment sold as TB-500 has essentially no dedicated research of its own, in animals or people, beyond the chemistry paper that identified it.
In humans, TB-500 itself has zero genuine registered trials. The only ClinicalTrials.gov record naming it, NCT07487363, states in its own summary that it is a fictional example. So there is no human safety or efficacy data for the fragment for any purpose, and whether it behaves like the parent protein is unknown. Anyone weighing it for their own health should talk to a physician. Sources are listed below.
Sources
- Esposito S et al., Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500 (DOI 10.1002/dta.1402)
- Drug Testing and Analysis, 2012
- ClinicalTrials.gov NCT00382174, thymosin beta 4 topical gel in pressure ulcers, Phase 2, n=72, results posted
- ClinicalTrials.gov, 2008
- ClinicalTrials.gov NCT03937882, RGN-259 thymosin beta 4 eye drops for dry eye (ARISE-3), Phase 3, n=700, results posted
- ClinicalTrials.gov, 2021
- ClinicalTrials.gov NCT07487363, record naming TB-500 that self-identifies as a fictional example record
- ClinicalTrials.gov, 2026
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