home / compounds / Follistatin 344
Follistatin 344
Myostatin-pathway protein. Dramatic animal results, no human validation.
What it is
A glycoprotein that binds and inhibits members of the TGF-beta family including myostatin.
What it does
Myostatin limits muscle growth; inhibiting it produced striking muscle increases in animal studies.
Does it work?
The animal images circulating online are real but come from genetic models, not injections in healthy humans. No controlled human trial supports the marketed use, and systemic TGF-beta interference carries theoretical risk.
Claims vs data
Each marketing claim, tagged by what the evidence actually supports.
| Dramatic muscle growth in humans | overreach |
| Inhibits myostatin | preclinical only |
Reference figures
Quoted from published reference material. These are not Peptuity recommendations.
The evidence, counted
Live counts from Europe PMC and ClinicalTrials.gov.
18 publications indexed, 0 registered interventional studies, no randomised controlled trials indexed. Evidence is minimal.
query: "Follistatin 344" · checked 2026-08-07
Most-cited literature
-
Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitors
Haidet AM, Rizo L, Handy C, Umapathi P, Eagle A, Shilling C, Boue D, M · Proc Natl Acad Sci U S A 2008 · 204 citations
-
Gene transfer demonstrates that muscle is not a primary target for non-cell-autonomous toxicity in familial amyotrophic lateral sclerosis
Miller TM, Kim SH, Yamanaka K, Hester M, Umapathi P, Arnson H, Rizo L, · Proc Natl Acad Sci U S A 2006 · 125 citations
-
Micro-dystrophin and follistatin co-delivery restores muscle function in aged DMD model
Rodino-Klapac LR, Janssen PM, Shontz KM, Canan B, Montgomery CL, Griff · Hum Mol Genet 2013 · 48 citations
-
Antisense-induced myostatin exon skipping leads to muscle hypertrophy in mice following octa-guanidine morpholino oligomer treatment
Kang JK, Malerba A, Popplewell L, Foster K, Dickson G. · Mol Ther 2011 · 48 citations
Regulatory status
Formal, dated regulatory actions.
WADA — Prohibited List 2026
Prohibited in sport — WADA S4 (hormone and metabolic modulators)
Common questions
Are the double-muscled animal photos real?
Yes — but they come from genetic myostatin knockouts, not from injecting follistatin into healthy adult animals or people.
Has follistatin ever been tried in humans?
A small gene-therapy trial in muscular dystrophy exists. That is very different from injectable peptide use in healthy people, which has no controlled evidence.
What is the theoretical risk?
Follistatin binds several TGF-beta family members, not just myostatin. Interfering with that system broadly has consequences nobody has mapped in humans.