P21 (P021)

Key points

• P21 is a small synthetic peptide derived from a natural nerve growth factor.
• It is studied for encouraging new nerve cells and protecting existing ones.
• All the evidence is from animal and laboratory work, aimed at conditions such as Alzheimer's disease.
• It is not a licensed medicine in the UK and is sold only for research use.

Quick facts

What it is

Experimental neurotrophic peptide

Studied for

Nerve cell growth; dementia research

UK status

Not a licensed medicine; sold for research use

Human evidence

None; animal and cell studies only

How it works

P21 is based on an active part of a natural factor that supports nerve cell growth and survival. In animal models it is studied for encouraging new nerve cells in the brain and reducing changes linked to dementia. How, and whether, this works in people is not established.

What the evidence shows

The evidence is preclinical, from animal models of ageing and dementia. There are no human trials, no established dose, and no safety data in people.

What it does not settle

• There are no human trials of benefit or safety.
• There is no established human dose.
• Long term effects are unknown.

Side effects

Less common but serious

• Human safety is unstudied, so the risks are not known.
• 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

P21 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 as a research chemical.

Common questions