TB-500
A synthetic peptide related to the natural protein Thymosin Beta-4, promoted for injury recovery and tissue repair. Like BPC-157, it has animal data but little human evidence.
Quick take
- What it is: a synthetic fragment based on Thymosin Beta-4, a naturally occurring repair protein.
- What people use it for: recovery from muscle, tendon and ligament injuries.
- What we actually know: promising tissue-repair effects in animals; no published human clinical trials.
- Status: not FDA-approved and banned in competitive sport.
What it is
TB-500 is a synthetic peptide based on an active region of Thymosin Beta-4 (Tβ4), a naturally occurring protein involved in cell migration, blood-vessel growth and tissue repair. Although the names are often used interchangeably in the peptide community, TB-500 and natural Thymosin Beta-4 are not strictly the same molecule.1
How it works
Thymosin Beta-4 binds actin, a protein central to cell structure and movement, and is thought to support healing by promoting cell migration into injured areas, encouraging new blood-vessel formation, and reducing inflammation.2 TB-500 is proposed to share these actions, which is the rationale behind its use for recovery.
What the evidence shows
The supportive evidence is largely preclinical. Animal and laboratory studies suggest Thymosin Beta-4 and related fragments can aid wound healing, cardiac repair and corneal healing.2,3 As with BPC-157, there are no published human clinical trials establishing that TB-500 is safe or effective for the recovery uses it is marketed for.
Dosages reported in the literature
Informational only. The figures below describe doses reported anecdotally and in non-human research. They are not a recommendation or a prescription and should not be read as established as safe or effective in people.
| Setting | Route | Reported range |
|---|---|---|
| Animal / lab research | Injection | Varies; not directly applicable to humans |
| Anecdotal / clinic-reported | Subcutaneous | Reported in low milligram amounts per week, often split into doses |
Reported protocols vary widely and are not backed by dose-finding human studies.
Safety & side effects
There are no long-term controlled human safety data for TB-500. Reported side effects are mostly anecdotal and include injection-site reactions and temporary fatigue or head-rush sensations. Because the product is unregulated, purity and dosing accuracy can vary considerably between sources — a key reason professional sourcing and oversight matter.
Legal & regulatory status
TB-500 is not approved by the FDA for any use. It is banned in competitive sport by the World Anti-Doping Agency under category S0 (non-approved substances).4 Regulations vary by country and change over time.
References
- 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 Jan;12(1):37-51. [PMID 22074294, doi:10.1517/14712598.2012.634793]
- Crockford D, Turjman N, Allan C, Angel J. Thymosin β4: structure, function, and biological properties supporting current and future clinical applications. Ann N Y Acad Sci. 2010 Apr;1194:179-89. [PMID 20537499, doi:10.1111/j.1749-6632.2010.05492.x]
- 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 Nov 25;432(7016):466-72. (Cardiac.) Companion corneal evidence: Sosne G, et al. Thymosin beta 4 promotes corneal wound healing and modulates inflammatory mediators in vivo. Exp Eye Res. 2002 Feb;74(2):293-9 (PMID: 11950239). [PMID 15565145, PMID 11950239, doi:10.1038/nature03000]
- World Anti-Doping Agency. The Prohibited List — Section S0: Non-Approved Substances (prohibited at all times). 2026 International Standard Prohibited List. [wada-ama.org, wada-ama.org]