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TB-500 Dr

The name and the record.

The reading list

TB-500 references

The fragment-identification papers and the human thymosin beta-4 studies have different questions in mind. This reading list includes both.

Studies grouped by the substance tested

For the fragment itself, Esposito's synthesis and characterization paper and Ho's equine detection paper establish the analytical starting point. Delcourt's preparation analysis brings the identity problem forward into later work.

For functional repair, the mdx mouse muscle experiment makes a useful companion to the rat wound study. I prefer them side by side: the first separates regeneration from strength, while the second records a specific resurfacing result.

The human record includes Ruff’s intravenous safety study, the placebo-controlled dry-eye study and the clinical-trial registrations below. The withdrawn injectable registration concerns acute myocardial infarction, not stroke. The FDA safety page, 503A framework and July meeting notice document regulatory proceedings; clinical efficacy requires trial evidence.

The full list follows. Its reference identity entry provides a definition rather than experimental evidence.

  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 β4 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 β4: 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 β4 in healthy volunteers. Ann N Y Acad Sci. 2010;1194:223-229. ↗
  7. Sosne G, Dunn SP, Kim C. Thymosin beta 4 ophthalmic solution for dry eye: a randomized, placebo-controlled, Phase II clinical trial conducted using the controlled adverse environment (CAE) model. Clin Ophthalmol. 2015;9:877-884. ↗
  8. Sosne G, Kleinman HK, et al. 0.1% RGN-259 (Thymosin β4) Ophthalmic Solution Promotes Healing and Improves Corneal Integrity. Int J Mol Sci. 2022;24(1):554. ↗
  9. RegeneRx / ReGenTree (sponsor). Assessment of the Safety and Efficacy of RGN-259 Ophthalmic Solutions for Dry Eye (ARISE-3). ClinicalTrials.gov identifier NCT03937882; 2020. ↗
  10. Efficacy and Safety Study of Thymosin Beta 4 in Patients With Acute Myocardial Infarction. ClinicalTrials.gov identifier NCT05984134; 2023. ↗
  11. RegeneRx (sponsor). A Study of the Safety and Efficacy of Injectable Thymosin Beta 4 for Treating Acute Myocardial Infarction (withdrawn). ClinicalTrials.gov identifier NCT01311518; 2011. ↗
  12. TB-500 (Ac-LKKTETQ), the synthetic N-acetylated heptapeptide fragment (residues 17-23) of thymosin beta-4; parent protein thymosin beta-4 / TMSB4X, UniProt P62328. Reference identity entry. ↗
  13. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026. ↗
  14. Wang L, et al. Thymosin β4 improves the survival of cutaneous flaps of rat and activates Wnt/β-catenin signaling. Arch Med Sci. 2024. ↗
  15. U.S. Food and Drug Administration. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act. FDA.gov (verified 2026-05-29). ↗
  16. Chen Y, et al. Thymosin β4 released from functionalized self-assembling peptide activates cardiac cells and promotes cardiac repair. Theranostics. 2021;11(10):4631-4647. ↗
  17. Esposito S, et al. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Test Anal. 2012;4(9):733-738. ↗
  18. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks — entry 'Thymosin beta-4, fragment (LKKTETQ), also known as TB-500' (formerly Category 2; nomination withdrawn; safety concerns retained; list entry effective 2023-09-29). FDA.gov (verified 2026-05-29). ↗
  19. 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 and the January 7, 2025 revised interim policy. FDA.gov (verified 2026-05-29). ↗
  20. U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee — agenda listing BPC-157, KPV, TB-500, and MOTs-C as bulk drug substances being considered for inclusion on the 503A Bulks List. FDA.gov (verified 2026-05-29). ↗
  21. Cha HJ, Jeong MJ, Kleinman HK. Role of thymosin beta4 in tumor metastasis and angiogenesis. J Natl Cancer Inst. 2003. ↗
  22. 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. ↗
  23. 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. ↗
  24. 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. ↗
  25. Delcourt V, et al.. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Test Anal. 2023. ↗