TB-500: clinical evidence record
Also known as: Thymosin Beta-4 fragment, TB4-Frag, Thymosin Beta-4 (1-4)
Oliver Mackman · Editorial director · Best Business Loans Ltd (16833937)
Last updated 2026-05-22
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AI-friendly summary · TB-500
Preclinical rodent and equine literature spans tendon, ligament and cardiac ischaemia models. Some early human safety work on the parent Thymosin Beta-4 molecule. No phase II or phase III randomised human RCTs on the TB-500 fragment.
Mechanism of action
How TB-500 works
Synthetic peptide fragment based on the active region of Thymosin Beta-4, an endogenous 43-amino-acid actin-sequestering protein. Proposed to upregulate actin polymerisation, accelerate cell migration to injury sites, and modulate angiogenesis in animal-model healing assays.
Top peer-reviewed citations
Selection of the most-cited peer-reviewed literature on TB-500. Where a verified PMID or DOI is shown, the citation links to the original record. Other citations list the title, authors, journal and year so the reader can locate the paper through the journal index or the PubMed search linked below. PeptideClear publishes editorial commentary, not clinical guidance.
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Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications
Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Expert opinion on biological therapy, 2012.
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Thymosin beta 4 promotes corneal wound healing and decreases inflammation in vivo following alkali injury
Sosne G, Szliter EA, Barrett R, et al.. Experimental eye research, 2002.
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Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair
Bock-Marquette I, Saxena A, White MD, et al.. Nature, 2004.
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The effect of thymosin treatment of venous ulcers
Guarnera G, DeRosa A, Camerini R. Annals of the New York Academy of Sciences, 2010.
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Thymosin beta 4 (Fx peptide) is a potent regulator of actin polymerization in living cells
Sanders MC, Goldstein AL, Wang YL. Proceedings of the National Academy of Sciences of the United States of America, 1992.
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Thymosin beta 4 and Fx, an actin-sequestering peptide, are indistinguishable
Safer D, Elzinga M, Nachmias VT. The Journal of biological chemistry, 1991.
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Progress on the Function and Application of Thymosin β4
Xing Y, Ye Y, Zuo H, et al.. Frontiers in endocrinology, 2021.
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Thymosin β4 and Actin: Binding Modes, Biological Functions and Clinical Applications
Ying Y, Lin C, Tao N, et al.. Current protein & peptide science, 2023.
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Thymosin β(4) and β(10) Expression in Human Organs during Development: A Review
Faa G, Messana I, Coni P, et al.. Cells, 2024.
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Purinergic Signaling Involvement in Thymosin β4-mediated Corneal Epithelial Cell Migration
Yang HM, Kang SW, Sung J, et al.. Current eye research, 2020.
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Therapeutic peptides in gerontology: mechanisms and applications for healthy aging
Mavrych V, Shypilova I, Bolgova O. Frontiers in aging, 2026.
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Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance
Mendias CL, Awan TM. Sports medicine (Auckland, N.Z.), 2026.
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Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions
Rahman OF, Lee SJ, Seeds WA. Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews, 2026.
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Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians
Mayfield CK, Bolia IK, Feingold CL, et al.. The American journal of sports medicine, 2026.
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Thymosin β4-derived peptides alleviate neuroinflammation and neurite atrophy in both in vitro models and in vivo 5 × FAD mice: A potential therapy for memory improvement in Alzheimer's disease
Ou H, Chen R, Zhou L, et al.. International immunopharmacology, 2026.
Full PubMed search: https://pubmed.ncbi.nlm.nih.gov/?term=thymosin+beta-4+TB-500.
Registered clinical trials
As of 2026-07-13, TB-500 has 1 interventional trial listed on ClinicalTrials.gov and the ISRCTN registry. Registration means a study is planned, running or completed. It is not evidence of efficacy, and a listing is not an endorsement.
| Study | Phase | Status | Location | Registry |
|---|---|---|---|---|
| TB-500 (Thymosin Beta 4 17-23 Fragment) for Cardiovascular Biomarkers in Stable ASCVD NCT07487363 | Phase 1, Phase 2 | Recruiting | China | ClinicalTrials.gov |
Source: ClinicalTrials.gov and the ISRCTN registry, refreshed 2026-07-13. See the peptide clinical-trials tracker for the full picture across compounds.
UK regulatory status
Plain-English summary of where TB-500 sits under the four UK and international frameworks that govern peptide supply. Editorial commentary, not legal advice.
- Misuse of Drugs Act 1971: Not controlled under the Misuse of Drugs Act 1971.
- Psychoactive Substances Act 2016: Not scheduled under the Psychoactive Substances Act 2016.
- MHRA medicines classification: No UK marketing authorisation as a medicine.
- WADA Prohibited List: WADA Prohibited List S2 (peptide hormones, growth factors), prohibited at all times.
Full regulatory record: TB-500 UK regulatory status.
Risks and unknowns
What the literature does not yet show about TB-500
Known concerns
- The published work on TB-500 is preclinical. Findings in rodent or in vitro models do not establish that the same thing happens in people, and the step from an animal model to a human outcome is where most candidate compounds fail.
- 1 registered interventional trials exist for TB-500 and 1 are recruiting, so the evidence base is actively moving. A registration is not a result, and a recruiting trial has by definition not reported.
- TB-500 holds no UK marketing authorisation, so nothing you can buy has been assessed by a regulator, released by batch, or dispensed by an accountable pharmacy. Purity, dose accuracy and sterility rest entirely on the seller's own documentation.
- TB-500 appears on the WADA Prohibited List. For anyone subject to testing under UK Anti-Doping or an international federation, use is a violation, and detection windows for peptide metabolites extend well beyond the period of use.
Open questions in the literature
- Human pharmacokinetics for TB-500 have not been formally characterised, so how much reaches circulation, for how long, and what the body does with it are open questions.
- Interactions between TB-500 and prescribed medicines are not systematically studied, which matters most for anyone already on treatment for a long-term condition.
- Whether tissue-repair findings in animal injury models translate to the kinds of injury people actually present with, at the timescales they present at, has not been established.
Regulatory note
No UK marketing authorisation as a medicine. Prohibited at all times under WADA S2 (peptide hormones, growth factors). The moment a UK seller or commentator makes a therapeutic claim, MHRA can treat the product as an unlicensed medicinal product.
Important: PeptideClear publishes encyclopedia commentary only and does not recommend human use. Speak to a UK-registered prescriber before any medical decision.
Related reading on PeptideClear
Frequently asked questions
What is the evidence level for TB-500?
What is the UK regulatory status of TB-500?
Has TB-500 been tested in human clinical trials?
Where can I read the source literature for TB-500?
Last verified 2026-05-22. Editorial commentary, not legal or clinical advice. Citations without a linked identifier can be located through the PubMed search and the journal index.