Skip to main content
TB-500 MD

A modular research dossier on TB-500 — the Ac-LKKTETQ fragment of thymosin beta-4 — tiling each muscle, tendon, and regulatory finding into its own panel, with the human-data gaps and the full-length-versus-fragment caveat surfaced in plain view.

SOURCES / 07

TB-500 references show what each study tested

Each note names the paper or FDA page. It also says whether researchers used people, animals, cells, the whole protein, or the fragment.

Return to study resultsCheck legal rules

Most listed studies used the whole protein

Where can you check the TB-500 claims? The papers and FDA pages appear below.

Most papers studied whole thymosin beta-4 rather than the short fragment. Each note says whether the test used people, animals, or cells.

That detail keeps a mouse result from looking like human proof. We took study facts from the listed papers.

We checked each legal fact on the date printed beside its FDA page. Every claim got the same check before we published it.

You can check the full paper names and links below. Some titles use lab terms because they are the papers' official names.

  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. Tokura Y, Nakayama Y, Fukada S, et al. Muscle injury-induced thymosin β4 acts as a chemoattractant for myoblasts. J Biochem. 2011;149(1):43-48. ↗
  8. Xu B, et al. Thymosin β4 enhances the healing of medial collateral ligament injury in rats. Regul Pept. 2013;184:1-8. ↗
  9. Spurney CF, Cha HJ, Sali A, et al. Evaluation of skeletal and cardiac muscle function after chronic administration of thymosin beta-4 in the dystrophin deficient mouse. PLoS One. 2010;5(1):e8976. ↗
  10. Jo JO, Kang YJ, Ock MS, et al. Thymosin β4 induces the expression of vascular endothelial growth factor (VEGF) in a hypoxia-inducible factor (HIF)-1α-dependent manner. Biochim Biophys Acta. 2010;1803(11):1244-1251. ↗
  11. Qiu P, Wheater MK, Qiu Y, Sosne G. Thymosin beta4 promotes matrix metalloproteinase expression during wound repair. J Cell Physiol. 2006;220(3):778-786. ↗
  12. Sosne G, Qiu P, Christopherson PL, Wheater MK. Thymosin beta 4 suppression of corneal NFkappaB: a potential anti-inflammatory pathway. Exp Eye Res. 2007;84(4):663-669. ↗
  13. 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. ↗
  14. Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026. ↗
  15. Gonzalez-Franquesa A, Gama-Perez P, Kud O, et al. Discovery of thymosin β4 as a human exerkine and growth factor. Am J Physiol Cell Physiol. 2021;321(5):C770-C778. ↗
  16. U.S. Food and Drug Administration. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee. FDA Advisory Committee Calendar. Lists BPC-157, KPV, TB-500, and MOTs-C as bulk drug substances being considered for inclusion on the 503A Bulks List (scheduled discussion; not a decision). ↗
  17. U.S. Food and Drug Administration. Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks. Records the September 29, 2023 Category 2 addition of 'Thymosin beta-4, fragment (LKKTETQ), also known as TB-500'; the FDA page, current as of April 22, 2026, says the nomination was withdrawn and the substance is no longer in Category 2. ↗
  18. U.S. Food and Drug Administration. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act. Defines the 503A/503B framework, the bulk-substance eligibility rule (USP/NF monograph, component of an approved drug, or on the FDA bulks list), the Category 1 and Category 2 distinction, and the January 7, 2025 change under which newly nominated substances are no longer placed into numbered categories. ↗
  19. Cha HJ, Jeong MJ, Kleinman HK. Role of thymosin beta4 in tumor metastasis and angiogenesis. J Natl Cancer Inst. 2003. ↗
  20. 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. ↗
  21. 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. ↗
  22. Delcourt V, et al. TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs. Drug Test Anal. 2023. ↗