Claimed effect · Follistatin 344

Does Follistatin 344 help with muscle growth / strength?

D
Grade D — no human evidence0 controlled · effect size: not measurable
Short answerNo human evidence. As of 10 September 2026, no controlled human trial has tested Follistatin 344 for muscle growth / strength. No human study of any kind has given follistatin protein by injection. The grey-market product has no clinical file, and a 344-residue glycoprotein injected subcutaneously would be expected to be cleared quickly and to bind targets far beyond muscle.

What the studies show

No human study of any kind has given follistatin protein by injection. The grey-market product has no clinical file, and a 344-residue glycoprotein injected subcutaneously would be expected to be cleared quickly and to bind targets far beyond muscle.

Animal studies, cell studies, or anecdotes only. This is where almost every viral peptide sits. Promising and proven are different words for a reason.

  1. 1
    Searches of PubMed and trial registries for injected follistatin in humans.LYO literature search, September 2026No human trial of the injected protein identified.

In context

Follistatin is a natural protein that binds and blocks myostatin, the signal that limits muscle growth; animals engineered to overexpress it become dramatically muscular. 'Follistatin 344' is the full-length form, sold as a lyophilised injectable for muscle. No human trial has ever tested injecting it. The only clinical data is a 2015 gene-therapy study in six men with Becker muscular dystrophy, in which a virus carrying the follistatin gene was injected into the thigh muscles — some walked further, some did not, and it is not the product being sold. It is prohibited in sport.

Follistatin 344 is not approved; research reagent. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is Follistatin 344 proven to help with muscle growth / strength?
No. There is no human evidence for it (0 controlled); the claim rests on animal or cell studies and LYO grades it D.
What studies are behind the grade?
No human study of any kind has given follistatin protein by injection. The grey-market product has no clinical file, and a 344-residue glycoprotein injected subcutaneously would be expected to be cleared quickly and to bind targets far beyond muscle.
Is Follistatin 344 approved for this?
No. Follistatin 344 is not approved; research reagent; it is not an approved medicine for any indication in the jurisdictions LYO covers.

Other outcomes for Follistatin 344

Written and maintained by LYO Research — how pages are written and checked. Reviewed 10 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →