PEG MGF

Key points

• PEG MGF is MGF with a chemical tag (PEG) added so it stays active longer in the blood.
• MGF is a local form of IGF-1 thought to help muscle repair after stress or damage.
• Human evidence as an injected product is very limited, as with MGF.
• It has no UK marketing authorisation, and growth factors are prohibited in sport.

Quick facts

What it is

Pegylated mechano growth factor (longer lasting MGF)

Marketed for

Muscle repair and growth

UK status

Not a licensed medicine; sold for research use

Human evidence

Very limited; mostly laboratory studies

In sport

On the WADA Prohibited List

How it works

Plain MGF acts locally and is broken down quickly. Adding a PEG tag is meant to let a dose circulate and act for longer. The underlying idea, switching on muscle repair through an IGF-1 signal, is the same as for MGF, and just as unproven in people.

What the evidence shows

There are no controlled human trials showing PEG MGF safely builds or repairs muscle. The science rests on the same cell and animal work as MGF, with no settled human dose.

What it does not settle

• There are no controlled human trials of benefit.
• Long term safety is unknown, and products are not quality assessed.
• As a growth factor, there is a theoretical concern about encouraging unwanted cell growth.

Side effects

Less common but serious

• As a growth factor, there is a theoretical concern about cancer, and injecting a product of unknown quality carries real risks.
• 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

PEG MGF 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