TB-500 (thymosin beta-4 fragment): what the research says
Also known as Ac-LKKTETQ, a 7-amino-acid piece of thymosin beta-4.
Not approved TB-500 (thymosin beta-4 fragment) is studied mostly in animals or the lab and not approved as a medicine.
Key facts
- What it is
- A short lab-made piece (7 amino acids, Ac-LKKTETQ) of the natural protein thymosin beta-4. It is not the full protein.
- What it was studied for
- Thymosin beta-4 binds actin, a building block inside cells. In animal and lab studies it helped cells move into wounds. Whether TB-500 does this in people is unknown.
- Human evidence
- FDA found no human studies of TB-500. The full thymosin beta-4 protein has been tested in people, for example as eye drops, which is a different product.
- Combined with BPC-157?
- Some people combine the two, but no human or controlled study has tested the combination. Any "synergy" is unproven.
Anti-doping (WADA) status
Prohibited by WADA at all times under S2 (growth factors). Thymosin beta-4 and its derivatives, such as TB-500, were added in 2018. It is also prohibited in horse racing.
Status in Nepal
Not approved as a medicine anywhere, so it is not expected to be registered with Nepal's Department of Drug Administration (DDA). Under Nepal's Drugs Act 2035, drugs must be registered before they are imported or sold.
Sources
- FDA briefing document on TB-500, Pharmacy Compounding Advisory Committee (July 2026)
- Goldstein, Hannappel & Kleinman, Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues (Trends Mol Med 2005, PubMed 16099219)
- Philp et al., The actin binding site on thymosin beta4 promotes angiogenesis (PubMed 14500546)
- USADA: 2018 Prohibited List, thymosin beta-4 and TB-500 added under S2
This page explains research. It is not a recommendation to use TB-500 (thymosin beta-4 fragment). Talk to a doctor before using any medicine.