TB-500
Thymosin Beta-4 (Tβ4) · synthetic fragment
The actin-regulating repair peptide with real early human trials
TB-500 is the research-market name for synthetic thymosin beta-4 — a naturally occurring 43-amino-acid protein present in nearly all human cells — or its active fragment. Tβ4 regulates actin, the protein cells use to build structure and move, which is why it appears in wound-healing, cardiac, and corneal repair research. Unusually for this space, pharmaceutical versions of Tβ4 have reached early human trials.
Looking to source TB-500? It's stocked at RGP Labs — code TB10 applies automatically at checkout.
View TB-500 →What the Research Actually Says
Every claim below is cited to the published literature and labeled by how far the evidence has actually progressed. Numbers refer to the reference list at the bottom of the page.
Dermal wound healing
Early human trialsFoundational animal work showed topical and injected Tβ4 accelerated wound closure and re-epithelialization. Pharmaceutical Tβ4 subsequently entered Phase 2 human trials for chronic wounds such as pressure and venous stasis ulcers.
Cardiac repair
Preclinical (cell & animal)A landmark Nature study reported that Tβ4 promoted heart-cell migration and survival after experimental myocardial infarction in mice — among the most-cited findings in the entire Tβ4 literature.
Corneal & eye repair
Early human trialsTβ4 eye drops (developed as RGN-259) have been studied in human trials for dry eye disease and neurotrophic keratopathy — the most clinically advanced application of the peptide.
Mechanism: actin regulation
Preclinical (cell & animal)Tβ4 is the body's main actin-sequestering peptide; by binding actin monomers it influences how cells move, divide, and rebuild damaged tissue. This well-characterized mechanism is what separates Tβ4 from peptides whose targets remain speculative.
Where the Evidence Stops
- ◆Human trial data comes from pharmaceutical-grade Tβ4 programs (e.g., RGN-259 eye drops) — not from the gray-market vials sold as 'TB-500.' Results don't automatically transfer.
- ◆Products sold as TB-500 vary: some are full-length Tβ4, others only the short active fragment. A COA is the only way to know which you're looking at.
- ◆No Tβ4 product is approved by any major regulator for systemic human use.
- ◆TB-500/Tβ4 is prohibited in competitive sport under the WADA code.
Research-grade TB-500, batch-documented
RGP Labs ships from the US and publishes a batch number and full specifications for every vial. Code TB10 takes 10% off — applied automatically at checkout.
Sold for laboratory research use only — not for human consumption.
Transparency: Peptide Insights has a disclosed referral relationship with RGP Labs and may earn a commission on purchases made through links or codes on this page. That never changes the price you pay or what the research above says. See our FAQ and disclaimer.
Not ready to decide about TB-500?
Our free guide covers TB-500 and nine other research peptides in depth — mechanisms, the state of the evidence, safety considerations, and a supplier-vetting checklist — across 12 chapters and 140+ citations.
References
- Malinda KM, et al. Thymosin beta4 accelerates wound healing. Journal of Investigative Dermatology, 1999.
- Bock-Marquette I, et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature, 2004.
- Goldstein AL, Hannappel E, Kleinman HK Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends in Molecular Medicine, 2005.
- Crockford D, et al. Thymosin beta4: structure, function, and biological properties supporting current and future clinical applications. Annals of the New York Academy of Sciences, 2010.
- Sosne G Thymosin beta 4 and the eye: the journey from bench to bedside. Expert Opinion on Biological Therapy, 2018.
More compound profiles
Published 2026-08-12. Reviewed against the cited primary literature.
This page is for educational purposes only and is not medical advice. Peptides discussed here are research compounds; nothing here is a recommendation to use them. Consult a qualified healthcare provider about anything affecting your health.