TB-500

Key points

• TB-500 is a laboratory made version of part of a natural protein called thymosin beta-4.
• It is studied mainly in animals, often for tendon, muscle and wound healing. Human evidence is very limited.
• It has no UK marketing authorisation and is not a licensed medicine in the UK.
• It is prohibited in sport.

Quick facts

UK status

Unlicensed

Legal supply

Not available as a licensed medicine

Class

Synthetic thymosin beta-4 fragment

Evidence

Mostly animal studies; very little human data

In sport

Prohibited (WADA Prohibited List)

How it works

Thymosin beta-4 helps cells move and organise during healing. TB-500 is a fragment designed to copy part of that effect. Most of what is known comes from laboratory and animal studies rather than good quality human trials.

What the evidence shows

The evidence is mostly from animal and laboratory work, with very little in people. Claims about faster recovery are not supported by the large, controlled human trials used to license a medicine.

What it does not settle

• There is little reliable human evidence of benefit.
• Long term safety in people is not established.
• Products sold as TB-500 are not checked for quality, purity or dose.

Side effects

Less common but serious

• Because there is no licensed product, the dose, purity and content of material bought from an unregulated seller are uncertain.

Report any suspected side effect through the MHRA Yellow Card scheme.

UK legal status and access

TB-500 has no UK marketing authorisation, so it is not a licensed medicine and is not offered by registered clinics or pharmacies. It is usually sold online labelled for research use. A research label does not mean a product has been assessed for safety, quality or dose.

Common questions