MGF

What people use it for

• Muscle repair and growth (popular use)
• Muscle and nerve repair (animal research)

What MGF does in the body

When muscle is stretched or damaged, it produces a variant of IGF-1 whose tail peptide, called MGF, appears to activate muscle stem cells. PEG-MGF has a polyethylene glycol chain attached so it lasts longer in the body.

Strength of evidence

Very weak: cell and animal studies only, with mixed results; no human trials.

Look up the evidence

• Reviews on PubMed: Summaries of the published research
• Clinical trials on PubMed: Published studies in people
• ClinicalTrials.gov: Registered trials, past and ongoing

Live searches of official databases. New to the terms? See the glossary.

Reported side effects & risks

• Injection-site reactions
• Unknown effects in humans
• Theoretical concern about growth signalling and cancer

Who should avoid it or take extra care

• Pregnant or breastfeeding
• Under 18
• Current or past cancer (it may promote cell growth; theoretical)
• Competitive athletes (prohibited by WADA)

Not a complete list. Check with a doctor or pharmacist about your own health and medicines.

Regulatory status

Not approved. Prohibited in sport by WADA (growth factors).

How it's taken

Route: Injection (popular use)

How long it lasts (half-life): Minutes for MGF; longer for PEG-MGF

Storage

Unreconstituted (powder) vials are usually kept refrigerated or frozen and away from light. Once mixed with bacteriostatic water, keep refrigerated and do not freeze; follow the supplier's stated beyond-use date.