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TB-500 Medicinal

A high-contrast research console on TB-500 (the Ac-LKKTETQ fragment of thymosin beta-4) — what the cardiac and tissue-repair literature actually establishes, where the human data stop, and how its regulatory standing reads.

Study papers and official pages · 07

Where do the numbered TB-500 references lead?

The small protein copy discussed for healing has little evidence from human studies. The papers and official sources below support the numbered notes. You can check the tested substance before weighing a treatment claim.

Read the findings about injuriesRead what the pharmacy rules mean

How do I find the source behind a numbered note?

The number beside a claim leads to its supporting TB-500 reference below. The sources help with your questions about wounds, stroke, heart damage, and Phase 1, the early human safety study. Others cover section 503A, the pharmacy law for medicine made for individual patients. Your first check is who took part: patients, animals, or cells kept in laboratory dishes.

Whole thymosin beta-4 differs from the copy and produced most of the healing findings. The research and heart pages name the substance used, because the findings are not interchangeable. FDA page dates describe when the agency's information was current, rather than proving when a request was withdrawn. The titles and identifying details below help you find the paper or official statement behind a claim.

  1. Irobi E, Aguda AH, Larsson M, et al. Structural basis of actin sequestration by thymosin-beta4: implications for WH2 proteins. EMBO J. 2004;23(18):3599-3608. ↗
  2. Bock-Marquette I, Saxena A, White MD, Dimaio JM, Srivastava D. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature. 2004;432(7016):466-472. ↗
  3. Malinda KM, Sidhu GS, Mani H, et al. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-368. ↗
  4. Morris DC, Cui Y, Cheung WL, et al. A dose-response study of thymosin beta4 for the treatment of acute stroke. J Neurol Sci. 2014;345(1-2):61-67. ↗
  5. Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin beta4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12(1):37-51. ↗
  6. Ruff D, Crockford D, Girardi G, Zhang Y. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin beta4 in healthy volunteers. Ann N Y Acad Sci. 2010;1194:223-229. ↗
  7. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026. ↗
  8. Stark C, Taimen P, Tarkia M, et al. Cardioprotection by systemic dosing of thymosin beta four following ischemic myocardial injury. Front Pharmacol. 2013;4:149. ↗
  9. Srivastava D, Saxena A, Dimaio JM, Bock-Marquette I. Thymosin beta4 and cardiac repair. Ann N Y Acad Sci. 2010;1194:87-96. ↗
  10. Peng H, Xu J, Yang XP, et al. Thymosin-beta4 prevents cardiac rupture and improves cardiac function in mice with myocardial infarction. Am J Physiol Heart Circ Physiol. 2014;307(5):H741-H751. ↗
  11. Smart N, Risebro CA, Melville AA, et al. Thymosin beta4 induces adult epicardial progenitor mobilization and neovascularization. Nature. 2007;445(7124):177-182. ↗
  12. TB-500 (thymosin beta-4 fragment) overview: human clinical-data status, pharmacokinetics, anti-doping (WADA) classification, and research/veterinary regulatory context. Compound corpus reference summary (tb-500, revision 2), drawing on the Ruff 2010 Phase 1 study (PMID 20536472), the ClinicalTrials.gov acute-MI registration NCT05984134, and the Mendias & Awan 2026 Sports Med review (PMID 41966639). ↗
  13. Wang Z, Su X, Ashraf M, et al. Thymosin beta4 increases cardiac cell proliferation, cell engraftment, and the reparative potency of mesenchymal stromal cells in a porcine model of myocardial infarction. Theranostics. 2021;11(16):7879-7895. ↗
  14. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks (entry for 'Thymosin beta-4, fragment (LKKTETQ), also known as TB-500'; its nomination was withdrawn and it is no longer in Category 2 on the agency page marked current April 22, 2026, with the prior September 29, 2023 placement and safety rationale) and FDA staff's briefing materials for the July 23-24, 2026 Pharmacy Compounding Advisory Committee meeting, which proposed that 'TB-500 (free base)' and 'TB-500 acetate' not be included on the 503A Bulks List. Verified 2026-05-29. ↗
  15. U.S. Food and Drug Administration. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act, and Interim Policy on Compounding Using Bulk Drug Substances Under Section 503A (Category 1 and Category 2 definitions; January 7, 2025 revised interim policy under which newly nominated substances are no longer placed in numbered categories and Category 2 substances are not afforded enforcement discretion). Verified 2026-05-29. ↗
  16. U.S. Food and Drug Administration. Human Drug Compounding: the 503A patient-specific and 503B outsourcing-facility framework and the bulk-substance eligibility requirement (lawful access via licensed-prescriber evaluation, valid patient-specific prescription, and a 503A pharmacy or 503B facility; ingredients flagged for significant safety risks are not eligible for routine 503A compounding). Verified 2026-05-29. ↗
  17. Cha HJ, Jeong MJ, Kleinman HK. Role of thymosin beta4 in tumor metastasis and angiogenesis. J Natl Cancer Inst. 2003. ↗
  18. Zhang Y, et al.. Thymosin beta 4 is overexpressed in human pancreatic cancer cells and stimulates proinflammatory cytokine secretion and JNK activation. Cancer Biol Ther. 2008. ↗
  19. Ho EN, et al.. Doping control analysis of TB-500, a synthetic version of an active region of thymosin β4, in equine urine and plasma by liquid chromatography-mass spectrometry. J Chromatogr A. 2012. ↗
  20. Spurney CF, et al.. Evaluation of skeletal and cardiac muscle function after chronic administration of thymosin beta-4 in the dystrophin deficient mouse. PLoS One. 2010. ↗
  21. Delcourt V, et al.. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Test Anal. 2023. ↗