Healing & injury · Muscle & recovery
TB-500, simplified.
Also called Thymosin beta-4 fragment
Early researchA lab-made piece of a natural repair protein. It is often paired with BPC-157 for injuries.
- Size
- 7 amino acids
- How it is taken
- Injection
- Status
- Research compound, under FDA review
What is it?
Thymosin beta-4 is a protein your cells use to move, build blood vessels and repair damage. TB-500 is a short active piece of it.
What studies show
- In animalsIt improved wound, muscle and heart repair in animal studies.
- In peopleThe full thymosin beta-4 protein was tested as eye drops and wound gels in people, with modest results. TB-500 itself has not been tested in people.
What we don’t know yet
- Whether the fragment works like the full protein.
- Long-term safety.
Side effects and cautions
- Banned in sport by WADA; horse-racing positives are common.
- Online product quality varies.
Is it legal?
Not FDA-approved. Included in the 2026 HHS compounding plan and reviewed by an FDA advisory committee in July 2026.
Common questions
What is TB-500?
A lab-made piece of a natural repair protein. It is often paired with BPC-157 for injuries. Thymosin beta-4 is a protein your cells use to move, build blood vessels and repair damage. TB-500 is a short active piece of it.
What does the research say about TB-500?
It improved wound, muscle and heart repair in animal studies. The full thymosin beta-4 protein was tested as eye drops and wound gels in people, with modest results. TB-500 itself has not been tested in people.
Is TB-500 FDA approved?
Not FDA-approved. Included in the 2026 HHS compounding plan and reviewed by an FDA advisory committee in July 2026.
What are the side effects of TB-500?
Banned in sport by WADA; horse-racing positives are common. Online product quality varies.
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This page explains published research in plain language. It is not medical advice, a diagnosis, or a recommendation to take anything, and it does not give dosing. Most peptides here are not FDA-approved, and products sold online vary widely in purity. Rules around peptides are changing, so check the current status and talk with a licensed clinician before starting anything. Last reviewed 2026-09-26.