TB-500 Fragment (17-23)

Key points

• This is a small fragment of TB-500, which itself relates to the natural protein thymosin beta-4.
• The fragment is the short region believed to drive the healing related activity.
• Evidence is from animal and laboratory work; human data is very limited.
• It has no UK marketing authorisation, and tissue repair peptides are prohibited in sport.

Quick facts

What it is

Short fragment of TB-500 (thymosin beta-4 region)

Studied for

Tissue repair

UK status

Not a licensed medicine; sold for research use

In sport

On the WADA Prohibited List

How it works

Thymosin beta-4 helps cells move and organise during healing. This fragment is the short active region thought to copy part of that effect. As with TB-500, what is known comes mainly from animal and laboratory studies, not human trials.

What the evidence shows

There is some animal and laboratory work, but no human trials establishing benefit, dose or safety. See the TB-500 entry for the wider picture.

What it does not settle

• There is little reliable human evidence.
• Long term safety in people is not established.
• Products are not checked for quality, purity or dose.

Side effects

Less common but serious

• Because there is no licensed product, the dose, purity and contents of material bought online cannot be verified.

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

UK legal status and access

TB-500 Fragment 17-23 has no UK marketing authorisation, so it is not a licensed medicine and is not offered by registered clinics or pharmacies. It is sold online labelled for research use.

Common questions