MGF / PEG-MGF

Also known as Mechano growth factor, pegylated MGF

A piece of IGF-1 that muscles make after hard training. "PEG-MGF" is a version made to last longer.

Quick facts

Status: Not an approved medicine
Evidence: Preclinical (cell and animal studies)
Taken as: Injection
Common sizes: MGF: 5 mg. PEG-MGF: 2 mg.
Category: Growth factor fragment (experimental)

How it works

In the lab it seems to wake up muscle stem cells after damage.

What people use it for

Muscle growth and repair (claimed)

What the research shows

Only cell and animal studies.
No human trials.

Side effects & risks

Unknown in humans
Banned in sport

Is it legal?

Not an approved medicine in the EU, UK or US. In most countries it is illegal to sell it for use in people. Products labelled "research use only" are not checked for quality or purity. Prohibited in sport (WADA Prohibited List).

Storage & safe handling

Mix with bacteriostatic water: let it run slowly down the inside of the vial and swirl gently — never shake.
Store the mixed vial in the fridge and follow the use-by period on the label.
Wipe the vial top with alcohol and use a new sterile needle and syringe every time.
Rotate injection sites so the same spot is not used again and again.
Put used needles in a sharps container, not the household bin.
Get medical help for redness that spreads, fever, swelling or trouble breathing.

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Sources: WADA Prohibited List; Goldspink G, research on mechano growth factor.
Last updated 12 October 2026. Information — not medical advice. PepTimer does not replace a doctor. Many peptides are not approved medicines in the EU, UK or US. Talk to a qualified healthcare provider before starting, changing or stopping any treatment.