SmartPeptide
Start Free
MuscleAnimal / preclinical only

Follistatin (FST-344)

Protein that binds and inhibits members of the TGF-β superfamily, most notably myostatin. Myostatin inhibition increases muscle mass in animals and in rare human genetic conditions (myostatin-deficient individuals). Heavy biohacking / bodybuilding interest. Limited human-trial data for any indication.

Educational only — not medical advice. SmartPeptide does not prescribe, diagnose, or treat. Always consult a licensed healthcare provider before using any peptide, supplement, medication, or protocol.

What the research shows

Robust preclinical evidence that follistatin / myostatin-pathway inhibition increases muscle mass in mice and primates. Limited human-trial data for muscular dystrophy (mixed results). No FDA-approved follistatin product for any indication.

What's still experimental

All human therapeutic use. Dosing, route, immunogenicity, cardiac safety, tendon-strength balance, and long-term effects are unestablished.

Anecdotal / community reports

Bodybuilding-community claims of accelerated muscle growth. Reports are confounded by training, diet, and stacking with other compounds. Quality verification of grey-market product is essentially impossible.

Anecdotal reports are NOT scientific evidence. They reflect personal experience and may not generalize.

FDA approval status

Source: openFDA + DailyMed (NIH/NLM)
No FDA-approved drug label exists for “Follistatin (FST-344)”. This peptide is not currently approved by the FDA as a finished pharmaceutical product. Any commercial product claiming FDA approval should be treated with suspicion.

Doses studied in research

No established dose range

What published trials tested or FDA-approved labels specify. Reporting research facts — not a SmartPeptide recommendation.

No FDA-approved or established trial dose range for this peptide. Anecdotal ranges discussed in community forums exist but are not supported by published clinical trials, and SmartPeptide will not publish unverified doses.

This is the honest answer for peptides like BPC-157, IGF-1 LR3, MOTS-c, Epitalon and similar research compounds — robust human dose- ranging studies have not been published. Always work with a licensed clinician familiar with experimental peptides if you are considering any use.

FDA enforcement & recalls

Live · openFDA Drug Enforcement API
No FDA enforcement actions (recalls, market withdrawals, safety alerts) on record for “Follistatin (FST-344)”. This is the expected baseline for most peptides — the absence of recalls does NOT imply general safety, only that no formal FDA enforcement has been initiated against approved formulations.

Mechanism & targets

ChEMBL · UniProt · Open Targets

Molecule (ChEMBL)

View on ChEMBL
Formula
C21H27N5O2

Protein targets (UniProt)

  • Follistatin
    P19883gene: FSTHomo sapiens· 344 aaReviewed

    Multifunctional regulatory protein whose primary function is to antagonize members of the transforming growth factor beta (TGF-beta) superfamily including activin, myostatin, GDF11 or bone morphogenetic proteins (BMPs) (PubMed:11279126, PubMed:16482217, PubMed:18535106). Mechanistically, binds to these ligands in the extracellular space, blocking their type II receptor-binding site to inhibit downstream signaling (PubMed:16482217). Plays an essential role in muscle fiber formation and growth bot…

Live research

PubMed · ClinicalTrials.gov · Europe PMC · OpenAlex
PubMed papers
3,974
total
Human studies
0
MeSH: humans
Clinical trials
0
published
Active trials
45
248 total registered

Europe PMC — 2,587,024 additional records

Includes EU/UK studies and PubMed Central full-text articles. Often surfaces research weeks before PubMed indexes it.

Research volume (OpenAlex topic graph)

Total works
8,003,212
all years
Last 5 years
3,023,487
recent activity
Open access
5,922,060
freely readable
OA share
74%
of all works

Human clinical evidence

Semantic Scholar · AI TLDRs · influence-ranked
Semantic Scholar API is currently rate-limited.

Human-study summaries for “follistatin OR myostatin inhibitor” are available on Semantic Scholar but the shared free-tier API quota is exhausted right now. Try refreshing in a few minutes, or check the PubMed and Europe PMC panels above for the same literature.

Research funding & verification

NIH RePORTER · CrossRef DOI registry

NIH-funded research

U.S. National Institutes of Health
Funded projects
58
all years
Top award sum
$10.3M
aggregate USD
Years covered
16
research span
Largest active / recent grants

Publication landscape

CrossRef · DOI registry
Indexed works (CrossRef)
278,898
all DOIs registered
Retracted papers
0
no retractions on record
Top funders of indexed research
  • National Natural Science Foundation of China6,472 works
  • National Institutes of Health2,529 works
  • National Cancer Institute1,023 works
  • National Research Foundation of Korea879 works
  • Japan Society for the Promotion of Science851 works
  • Ministry of Education, Culture, Sports, Science and Technology812 works

Funder diversity is a credibility signal. Research concentrated in a single drug company's funding warrants more scrutiny than research funded across NIH, charities, and academic grants.

Preprints — cutting edge

bioRxiv · medRxiv · via Europe PMC

Preprints have NOT been peer-reviewed. They are early research shared by authors before formal validation. Treat findings as preliminary.

Showing 6 of 33,761 preprints indexed by Europe PMC.

Known risks

Theoretical cardiovascular concerns (myostatin pathway affects cardiac muscle), tendon/ligament strain mismatched to muscle growth, fibrosis. Pharmacokinetics and immunogenicity of recombinant follistatin in chronic use are poorly characterized. Source quality is a major concern.

Reported side effects

Injection-site reactions. Long-term tolerability poorly characterized in humans.

FDA adverse event reports (FAERS)

Updated quarterly by FDA
No reports found in the FDA Adverse Event Reporting System for “Follistatin (FST-344)”. This is normal for research-only peptides that are not marketed as FDA-approved drugs.

What requires medical supervision

Not FDA-approved. Should only be considered under specialty care for genetic muscle disease where appropriate.

Questions for your clinician

  • Do I have an indication where myostatin inhibition is being studied?
  • What FDA-approved muscle-mass interventions should we exhaust first?
  • What's the cardiac monitoring plan if we proceed?

Editorially curated references

Discussions about Follistatin (FST-344)

Start a discussion
No discussions yet — be the first. Share what you've learned, what worked, what didn't, or a study you want translated into plain English.
See all Follistatin (FST-344) discussions Native, moderated, no buying or selling