# TB-500 References: The Cited Thymosin Beta-4 and FDA Source Record | TB-500

> TB-500 references and citations: every PubMed study, DOI, and FDA source behind the thymosin beta-4 mechanism, tissue-repair, safety, and 503A regulatory claims on this site.

Every quantitative claim on this site resolves to one of these records: PubMed studies on thymosin beta-4, and the FDA pages behind the 503A status. Indexed and linkable.

## How this record is cited

This is the index of [TB-500 references and citations](/references) behind every claim on the site. Every quantitative statement — every dose, percentage, residue count, molecular weight, and regulatory fact — resolves to a numbered record below. The peptide-science citations are PubMed-indexed studies on thymosin beta-4 and its fragment; the regulatory citations are FDA pages and one law-firm analysis, each verified against a live primary source.

The single most important thing to read in this list is the species and molecule column. The majority of the efficacy citations — wound healing [3], cardiac repair [2], angiogenesis [14] — were generated with full-length thymosin beta-4, not the TB-500 heptapeptide. That is why the site flags the fragment-versus-protein distinction throughout: it is in the sources, not invented for emphasis.

## References

[1] Irobi E, et al. Structural basis of actin sequestration by thymosin-beta4: implications for WH2 proteins. EMBO J. 2004;23(18):3599-3608. https://pubmed.ncbi.nlm.nih.gov/15329672/
[2] 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. https://pubmed.ncbi.nlm.nih.gov/15565145/
[3] Malinda KM, et al. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113(3):364-368. https://pubmed.ncbi.nlm.nih.gov/10469335/
[4] 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. https://pubmed.ncbi.nlm.nih.gov/25060418/
[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. https://pubmed.ncbi.nlm.nih.gov/22074294/
[6] 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. https://pubmed.ncbi.nlm.nih.gov/20536472/
[7] Qiu P, et al. Thymosin beta4 promotes matrix metalloproteinase expression during wound repair. J Cell Physiol. 2007;212(2):548-558. https://pubmed.ncbi.nlm.nih.gov/16607611/
[8] Sosne G, et al. Thymosin beta 4 suppression of corneal NFkappaB: a potential anti-inflammatory pathway. Exp Eye Res. 2007;84(4):663-669. https://pubmed.ncbi.nlm.nih.gov/17254567/
[9] Stark C, et al. Cardioprotection by systemic dosing of thymosin beta four following ischemic myocardial injury. Front Pharmacol. 2013;4:149. https://pubmed.ncbi.nlm.nih.gov/24348421/
[10] Mendias CL, Awan TM. Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance. Sports Med. 2026. https://pubmed.ncbi.nlm.nih.gov/41966639/
[11] Lee Y, et al. Thymosin β4 Regulates Tissue Inflammatory Response in Mouse Nonalcoholic Fatty Liver Disease. J Inflamm Res. 2025;18:5959-5974. https://pubmed.ncbi.nlm.nih.gov/40322536/
[12] Wei Y, et al. Inhaled exogenous thymosin beta 4 suppresses bleomycin-induced pulmonary fibrosis. J Pharm Pharmacol. 2024;76(12):1594-1605. https://pubmed.ncbi.nlm.nih.gov/39579076/
[13] Chen Y, et al. Thymosin β4 released from functionalized self-assembling peptide activates cardiac cells and promotes cardiac repair. Theranostics. 2021;11(10):4974-4992. https://pubmed.ncbi.nlm.nih.gov/33754060/
[14] Zhang Y, et al. Tβ4-exosome-loaded hemostatic and antibacterial hydrogel to improve vascularized wound repair. Mater Today Bio. 2025;32:101585. https://doi.org/10.1016/j.mtbio.2025.101585
[15] Su Y, et al. Thymosin β4 promotes zebrafish Mauthner axon regeneration by facilitating actin dynamics. BMC Biol. 2024;22(1):238. https://pubmed.ncbi.nlm.nih.gov/39443925/
[16] FDA. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee. U.S. Food and Drug Administration advisory-committee calendar. Lists 'TB-500 (free base),' 'TB-500 acetate,' BPC-157, KPV, and MOTs-C as bulk drug substances being considered for inclusion on the 503A Bulks List (scheduled discussion, not a decision). https://www.fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-compounding-advisory-committee-07232026
[17] FDA. Certain Bulk Drug Substances for Use in Compounding That May Present Significant Safety Risks. U.S. Food and Drug Administration. Lists 'Thymosin beta-4, fragment (LKKTETQ), also known as TB-500' in Category 2 (effective with the September 29, 2023 update), citing potential immunogenicity for certain routes and a lack of important safety information. https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks
[18] FDA. Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act. U.S. Food and Drug Administration. Definitions of the 503A/503B framework and Category 1 / Category 2; statement that substances nominated on or after January 7, 2025 are not placed into these categories. https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act
[19] McDermott Will & Emery. End of an Era: FDA Retires 2017 Interim Policies for Bulk Drug Lists. Legal analysis of the January 7, 2025 FDA action confirming that existing Category 1 substances retain enforcement discretion while Category 2 substances do not regain it even with updated nominations. https://www.mcdermottlaw.com/insights/end-of-an-era-fda-retires-2017-interim-policies-for-bulk-drug-lists/
[20] FDA. Compounding and the FDA: Questions and Answers (Section 503A patient-specific compounding and Section 503B outsourcing facilities). U.S. Food and Drug Administration. Basis for the lawful access pathway: licensed-prescriber evaluation and valid patient-specific prescription, dispensed by a 503A pharmacy or 503B outsourcing facility, using only eligible bulk substances. https://www.fda.gov/drugs/human-drug-compounding/compounding-and-fda-questions-and-answers

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A phosphor-terminal reading of the TB-500 record — the Ac-LKKTETQ fragment logged green where its studies hold, every full-length thymosin beta-4 substitution flagged as a checksum mismatch, and the empty human-trial line left blinking NULL; no clinic behind the screen and nothing here dispensed or sold.