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Why this evidence grade
Animal studies only
TB-500 itself has essentially no human trials. Full-length thymosin beta-4, a related but different molecule, has been tested in small clinical trials for the eye and heart.
What it is
Thymosin beta-4 (Tβ4) is a 43-amino-acid protein made naturally by the body that binds actin. "TB-500" is the name vendors use for a shorter synthetic fragment (reported as the active region of the protein). Many claims about TB-500 are borrowed from research on full-length Tβ4, which is not the same product.
How it is thought to work
Tβ4 binds actin, which helps cells migrate, and is reported to promote new blood vessel formation and reduce inflammation in injury models. These findings come from cell and animal work on the full protein. Whether the TB-500 fragment reproduces those effects in people has not been shown in controlled studies.
What the studies found6 studies explained
Recombinant full-length Tβ4 has been tested in small human trials, including a randomized trial in 96 heart-attack patients where the overall difference in infarct size was not significant. Animal work shows faster healing of corneal and skin wounds. For TB-500 itself, published human efficacy data are essentially absent.
Goldstein AL, Hannappel E, Sosne G · Expert Opin Biol Ther · 2012 · PMID 22074294
reviewNarrative review
Who / how many
Basic biology and clinical programme overview
What they found
Summarises thymosin beta-4 as a repair-and-regeneration signal: binds actin, supports cell migration, reduces inflammation and scarring in skin, eye, heart and brain injury models.
Limitations
Written by researchers involved in developing Tβ4 therapies, so it leans optimistic. Covers the full protein, not TB-500.
Zhang Y, Dong Q, Bian X · Cardiovasc Res · 2025 · PMID 41229390
humanMouse experiments plus a randomized, double-blind, placebo-controlled trial
Who / how many
96 patients after heart attack (STEMI)
What they found
In mice, recombinant Tβ4 reduced cardiac damage after ischemia. In patients, infarct size fell significantly in the subgroup dosed within 8 hours of PCI, but overall differences between all treated and placebo patients were not significant.
Limitations
Full-length recombinant Tβ4, not TB-500. The headline benefit is in a subgroup, which makes it exploratory. The authors call for larger trials.
Kleinman HK, Sosne G · Vitam Horm · 2016 · PMID 27450738
reviewNarrative review
Who / how many
Thymosin beta-4 in dermal wound healing
What they found
Reports that full-length thymosin beta-4 increased healing rates in animal wound models (including diabetic and aged animals and burns) and in phase 2 trials of pressure ulcers, venous stasis ulcers and epidermolysis bullosa wounds, and was well tolerated.
Limitations
Written by researchers who developed thymosin beta-4 therapies. Phase 2 trials are small, and the work concerns the full protein, not TB-500.
20 trials on ClinicalTrials.gov list TB-500 as an intervention; the most advanced are shown. Registration is not evidence of benefit: many trials are ongoing, unpublished or never reported results.
Data pulled from the ClinicalTrials.gov API. Check sponsors: several newer peptide registrations come from companies that also sell the product.
European research
571 records in Europe PMC mention TB-500 in the title or abstract. Of the 25 most-cited with European author affiliations that we sampled, the most common countries were Germany (9), France (6), Sweden (2), UK (2).
Human safety data for TB-500 is lacking. Theoretical concerns include effects on cell migration and blood vessel growth in people with cancer; Tβ4 expression is elevated in some tumours, though that does not show the peptide causes cancer. Quality and purity of grey-market products are the largest practical risk.
Legal status
United States
Not FDA-approved. Compounding status was under active review in 2026 (an FDA advisory committee narrowly voted in July 2026 to recommend easing restrictions on several peptides including TB-500); confirm the current FDA position before relying on it.
Canada
Not authorized by Health Canada. Named in a Health Canada public advisory as an unauthorized injectable peptide.
European Union
No EU marketing authorization from the EMA. Sold online as a research chemical; not a lawful medicine or supplement in the EU.
Sport (WADA)
Prohibited at all times in sport (thymosin beta-4 and its derivatives, e.g. TB-500).
No. Thymosin beta-4 is the full 43-amino-acid protein. TB-500 is sold as a shorter fragment. Evidence for one does not transfer automatically to the other.
Does TB-500 have human studies?
Not in any meaningful way. Human trials exist for full-length recombinant thymosin beta-4 in the eye and heart, with mixed results.
