Peptide Graded

Follistatin-344

Does Follistatin-344 work?

Not properly: animal or lab studies, or small uncontrolled human reports. Two gene therapy studies of six patients each, no comparison group.

CAnimal and cell studiesNot approvedas of 2026-10-27

For muscle growth, the use follistatin-344 is sold for, the human evidence is two open-label gene therapy trials of six patients each, in Becker muscular dystrophy and inclusion body myositis, with no placebo arm. The dramatic muscle phenotypes come from mice lacking myostatin, not from giving follistatin to anyone. Since 2022 a few small company-run early-phase studies have also given the gene therapy to people. No study has tested the injected peptide in humans. 1456

In the first trial, six men had Becker muscular dystrophy. They received a gene therapy vector (AAV1) carrying the follistatin-344 gene. It was injected directly into the thigh muscles of both legs. Over a year, four of the six walked farther in a six-minute walk test, by 29 to 125 meters. Two did not improve. Muscle biopsies showed less fibrosis and larger fibers. There was no placebo group. 24

A follow-up report at two years found the walking gains held in the responders. 3

Evidence checklist

  • Randomised controlled trial Two open-label trials, no placebo
  • Human study over 100 people Six patients in each trial
  • More than one research group Gene therapy trials from related academic groups
  • Clinical outcomes, not surrogate markers Walk distance and muscle biopsies
  • Human safety data beyond case reports Gene therapy only; injected protein untested

Read the full Follistatin-344 page

More on Follistatin-344

Citations

  1. McPherron 1997, Nature: regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member (myostatin) doi.org
  2. Mendell 2015, Molecular Therapy: a phase 1/2a follistatin gene therapy trial for Becker muscular dystrophy (DOI record) doi.org
  3. Al-Zaidy 2015, Journal of Neuromuscular Diseases: follistatin gene therapy improves ambulation in Becker muscular dystrophy doi.org
  4. Mendell 2015, Molecular Therapy: a phase 1/2a follistatin gene therapy trial for Becker muscular dystrophy pubmed.ncbi.nlm.nih.gov
  5. Mendell 2017, Molecular Therapy: follistatin gene therapy for sporadic inclusion body myositis improves functional outcomes pubmed.ncbi.nlm.nih.gov
  6. ClinicalTrials.gov: follistatin intervention studies clinicaltrials.gov

Reference information only, not medical advice. Drawn from the Follistatin-344 article, fact-checked against the cited sources. No dosing anywhere on this site.