Follistatin-344

What people use it for

• Muscle growth (popular use)
• Muscular dystrophy (gene therapy research)

What Follistatin-344 does in the body

Follistatin binds and neutralises myostatin and activin, proteins that limit muscle growth. In animals, raising follistatin leads to larger muscles. Research has mostly delivered it by gene therapy rather than injecting the protein.

Strength of evidence

Very weak for injected products: animal studies and small early gene therapy trials; no trials of the products sold online.

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

• Unknown in humans
• Theoretical effects on fertility hormones, because activin helps control FSH
• Injection-site reactions

Who should avoid it or take extra care

• Pregnant, breastfeeding or trying to conceive
• 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 (myostatin inhibitors).

How it's taken

Route: Injection (popular use)

How long it lasts (half-life): Not well established

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.