For Research Use Only – Not for Human Consumption. For Research Use Only. Not for Human Consumption. Not for diagnostic, therapeutic or medical use. Statements have not been evaluated by the FDA.
TB-500 and Thymosin Beta-4: What Is Known and What Is Not
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Key points
- TB-500 is a synthetic fragment associated with the natural protein thymosin beta-4.
- TB-500 itself has no published human trials; full-length thymosin beta-4 has extensive animal data and one Phase III eye-drop trial.
- Not FDA-approved and prohibited in sport by WADA.
What it is
TB-500 is a research peptide linked to thymosin beta-4, a naturally occurring protein of about 43 amino acids that binds actin, the building block of a cell's internal scaffolding. TB-500 is sold as a fragment containing the actin-binding region.
How researchers study it
Typical experiments involve how cells migrate, how the cytoskeleton is organized, and how tissue remodels in wound-type models. Related work looks at signaling tied to blood vessel formation.
What the evidence shows
There are no published human trials of TB-500 itself. The wider thymosin beta-4 literature is large but mostly animal-based, with a single Phase III eye-drop trial being the main human exception. Results from the full-length protein do not automatically carry over to a fragment.
Regulatory status
TB-500 is not FDA-approved for any use. A July 2026 FDA advisory panel gave a favorable, non-binding vote on a compounding question, and it remains prohibited in sport by WADA.
