Peptide Graded

Thymosin beta-4

Does Thymosin beta-4 work?

Partly: small trials of up to 96 people, none on the injury use it is sold for.

BSome human evidenceNot approvedas of 2026-10-27

Thymosin beta-4 has two phase 1 safety trials in healthy volunteers (40 and 84 subjects), an 18-patient phase 3 eye-drop trial, a 96-patient randomized trial after heart attack, and a venous ulcer study. All are small and most tested topical or intravenous full-length protein for specific diseases, not the injected wound-healing use it is sold for. Animal work in rats and mice supports wound and cardiac effects. Grade B for the clinical indications under study; the injury-recovery use sold online has no trial. 47101112

Two randomized phase 1 trials tested healthy volunteers. One gave 40 Americans a single dose and a 14-day course into a vein. The other gave 84 Chinese volunteers a single dose and a 10-day course. Both found only mild to moderate side effects. They found no dose-limiting toxicity and no drug buildup. 1011

The phase 3 trial of RGN-259 eye drops in neurotrophic keratopathy randomized 18 patients. After four weeks, 6 of 10 treated patients had fully healed. So had 1 of 8 on placebo. That missed statistical significance on the main measure. But discomfort and dryness scores improved significantly. A larger phase 3 trial is registered. 49

Evidence checklist

  • Randomised controlled trial Small randomized trials in eye, heart
  • Human study over 100 people Largest trial 96; phase 1 had 84
  • More than one research group Trials from several groups and sponsors
  • Clinical outcomes, not surrogate markers Eye-drop missed primary endpoint; heart pending
  • Human safety data beyond case reports Volunteer trials only; no data on injection use

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More on Thymosin beta-4

Citations

  1. Goldstein 2012, Expert Opin Biol Ther: Thymosin beta4, a multifunctional regenerative peptide doi.org
  2. Guarnera 2007, Ann N Y Acad Sci: Thymosin beta-4 and venous ulcers, European randomized study doi.org
  3. ClinicalTrials.gov NCT03937882: RGN-259 phase 3 in dry eye clinicaltrials.gov
  4. Sosne 2022, Int J Mol Sci: RGN-259 in neurotrophic keratopathy, phase 3 pubmed.ncbi.nlm.nih.gov
  5. 2026, Peptides: Thymosin beta 4, an emerging therapeutic candidate for kidney diseases pubmed.ncbi.nlm.nih.gov
  6. Ho 2012, J Chromatogr A: Doping control analysis of TB-500 in equine urine and plasma pubmed.ncbi.nlm.nih.gov
  7. 2025, Cardiovasc Res: Recombinant human thymosin beta 4 in mice and STEMI patients after reperfusion pubmed.ncbi.nlm.nih.gov
  8. FDA: Certain bulk drug substances for use in compounding may present significant safety risks fda.gov
  9. ClinicalTrials.gov NCT05555589: RGN-259 phase 3 in neurotrophic keratopathy clinicaltrials.gov
  10. Ruff 2010, Ann N Y Acad Sci: Randomized placebo-controlled single and multiple dose study of intravenous thymosin beta4 in healthy volunteers pubmed.ncbi.nlm.nih.gov
  11. 2021, J Cell Mol Med: First-in-human phase 1 study of recombinant thymosin beta4 in healthy Chinese volunteers pubmed.ncbi.nlm.nih.gov
  12. Malinda 1999, J Invest Dermatol: Thymosin beta4 accelerates wound healing pubmed.ncbi.nlm.nih.gov
  13. STAT 2026: FDA panel to discuss broader access to peptides via compounding statnews.com
  14. STAT 2026: FDA peptide compounding panel backs epitalon, rejects emideltide statnews.com

Reference information only, not medical advice. Drawn from the Thymosin beta-4 article, fact-checked against the cited sources. No dosing anywhere on this site.