Peptide library / Bones & muscles / Thymosin beta-4
Thymosin beta-4
A 43 amino acid protein present in nearly all human cells, studied for eye, heart and skin repair.
Effects studied or claimed
What it is used or promoted for, and where each effect has actually been seen
- Dry eye and corneal healingSmall human studies
- Wound healingSmall human studies
- Heart muscle repair after injuryAnimals
How it is thought to work
Thymosin beta-4 binds actin and is released at sites of injury, where it promotes cell migration and new blood vessel growth.
What the evidence shows
Eye drops of the full-length protein were tested in phase 3 trials for dry eye and neurotrophic keratitis with mixed results.
Safety and unknowns
Eye drops were well tolerated in trials. Injected use has not been established.
Regulatory status
Not approved. Studied as RGN-259 for eye conditions.
Regulatory status changes quickly. This entry was last reviewed on 27 October 2026. Confirm current status with the FDA before relying on it.
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General information, not medical advice. Do not buy or inject unregulated peptides.