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TB-500 Source

A precision research ledger on TB-500 (Ac-LKKTETQ) — the actin-binding thymosin beta-4 fragment tracked study by study, with the human-data gaps and compounded-access status reconciled in plain figures.

SOURCES BEHIND THE CLAIMS

TB-500 References: Check the Study Behind the Claim

For each claim, this list identifies who was studied, what happened, and the kind of source.

Return to the findingsCheck the current rules

How to check each claim against this list

Each number used on the TB-500 pages points to an item below. Most items are studies or reviews. Entries 13 through 16 are agency and sports-ban sources.

Before you trust a result, check who received the substance. Many studies used full thymosin beta-4, not the short chain. The same paper can be quoted correctly or stretched too far.

Each entry also gives library codes that help find the full paper. You don't need those codes to read the plain summary. Your doctor or a librarian can use them to pull up the paper.

  1. Irobi E, et al. Structural basis of actin sequestration by thymosin-beta4: implications for WH2 proteins. EMBO J. 2004;23(18):3599-3608. ↗
  2. Safer D, Elzinga M, Nachmias VT. Interaction of thymosin beta 4 with muscle and platelet actin: implications for actin sequestration in resting platelets. Biochemistry. 1992;31(31):6814-6821. ↗
  3. Philp D, et al. Thymosin beta 4 and a synthetic peptide containing its actin-binding domain promote dermal wound repair in db/db diabetic mice and in aged mice. Wound Repair Regen. 2003;11(1):19-24. ↗
  4. Goldstein AL, Kleinman HK. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med. 2005;11(9):421-429. ↗
  5. Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12(1):37-51. ↗
  6. Bock-Marquette I, et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature. 2004;432(7016):466-472. ↗
  7. Malinda KM, et al. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-368. ↗
  8. Morris DC, et al. A dose-response study of thymosin β4 for the treatment of acute stroke. J Neurol Sci. 2014;345(1-2):61-67. ↗
  9. Morris DC, et al. Thymosin beta4 improves functional neurological outcome in a rat model of embolic stroke. Neuroscience. 2010;169(2):674-682. ↗
  10. Ruff D, et al. A randomized, placebo-controlled, single and multiple dose study of intravenous thymosin β4 in healthy volunteers. Ann N Y Acad Sci. 2010;1194:223-229. ↗
  11. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026. ↗
  12. Sosne G, et al. Activation of pro-resolving pathways mediate the therapeutic effects of thymosin beta-4. Front Immunol. 2024;15:1458684. ↗
  13. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks (Category 2 entry: "Thymosin beta-4, fragment (LKKTETQ), also known as TB-500"; list entry effective September 29, 2023). ↗
  14. U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee (agenda lists BPC-157, KPV, TB-500 and MOTs-C as bulk drug substances being considered for inclusion on the 503A Bulks List). ↗
  15. U.S. Food and Drug Administration. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act (Category 1 / Category 2 definitions; 503A and 503B framework). ↗
  16. World Anti-Doping Agency. The Prohibited List (TB-500 / thymosin beta-4 prohibited under peptide/growth-factor and tissue-repair categories; detectable by LC-MS in equine and human matrices). ↗
  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. ↗