2009 · FINDING
CITEDKota et al. — primate trial
AAV-delivered follistatin in macaques produced sustained muscle fiber hypertrophy.
⚠ RESEARCH USE ONLY · NOT FDA-APPROVED FOR HUMAN USE · NOT MEDICAL ADVICE
MUSCLE & RECOVERYRESEARCH
Follistatin-344.
Myostatin inhibitor — the hypertrophy unlock
AKA · FS-344 · ACE-083 (analog)
MUSCLE & RECOVERYSUBCUTANEOUSINTRAMUSCULAR
A 344-residue protein that binds and inhibits myostatin, the body’s primary brake on muscle growth. Animal data is jaw-dropping; human data is thin and complicated.
~1.5 days
Half-life
3
Citations
2
Routes
1
Categories
72
Popularity
AT A GLANCE.
§ 01 · TL;DRTHE QUICK READ.
A 344-residue protein that binds and inhibits myostatin, the body’s primary brake on muscle growth. Animal data is jaw-dropping; human data is thin and complicated.
Myostatin normally caps how much muscle you can build. Follistatin binds myostatin and neutralizes it, releasing the brake.
Reports suggest short cycles (4–10 weeks). Effects beyond that not characterized.
WHAT IT MIGHT HELP WITH.
1
Increased lean muscle mass (animal models show dramatic hypertrophy)
2
Potential utility in muscular dystrophy research
3
Improved strength output in rodent studies
4
Accelerated recovery from atrophy (disuse / immobilization)
HOW IT WORKS.
§ 02 · MECHANISMMyostatin normally caps how much muscle you can build. Follistatin binds myostatin and neutralizes it, releasing the brake.
Follistatin-344 sequesters myostatin (GDF-8) and activin, preventing ActRIIB receptor activation. Downstream, SMAD 2/3 phosphorylation decreases, allowing satellite cell proliferation and protein synthesis via mTOR.
WHO IT'S FOR
- ✓Researchers studying myostatin pathways
- ✓Sarcopenia / muscular dystrophy models
WHO SHOULD AVOID
- ✕Anyone without physician oversight
- ✕Cardiac history
- ✕Pregnancy
THE RESEARCH.
§ 03 · 3 STUDIES2015 · FINDING
CITEDMendell et al. — Becker MD
Gene-therapy follistatin in 6 Becker MD patients improved 6-minute walk test at 1 year.
2020 · FINDING
ACE-083 Phase II
Analog locally injected showed significant muscle volume increases vs. contralateral control.
DOSING PROTOCOL.
§ 04 · DOSINGTYPICAL RANGE
Reports suggest short cycles (4–10 weeks). Effects beyond that not characterized.
100mcg subcutaneous daily (reported research range; highly variable)
FREQUENCY
Most-cited schedule
Once daily
ROUTES
Delivery methods
SUBCUTANEOUS · INTRAMUSCULAR
HALF-LIFE
Steady state drives frequency
~1.5 days
⚠ NOTE
These are reported protocols from research literature and practitioner accounts, not prescriptions. No FDA-approved human dose exists for research compounds. Anyone using Follistatin-344 should work with a qualified physician and source from a supplier providing third-party COAs.
FORMS AVAILABLE
- · Lyophilized vial, 1mg typical
⚠ RESEARCH INFORMATION ONLY · NOT MEDICAL ADVICE
SIDE EFFECTS & RISKS.
§ 06 · SAFETY·
Injection site reactions
Common · mild
•
Increased cortisol
Reported · moderate
Activin suppression affects HPA axis
!
Unknown long-term cardiovascular effects
Unknown · serious
Myostatin plays roles outside skeletal muscle
!
Theoretical cardiac hypertrophy
Theoretical · serious
WHERE TO SOURCE
§ 07 · SUPPLIERPEAK LAB
PEPTIDES
PEPTIDES
SUPPLIER OF RECORD · 12 BATCHES PASSED
We tried nine suppliers across 2025 and kept picking PEAK LAB for Follistatin-344: 99.4% HPLC purity, COA on every batch, cold chain intact. Shop through our link and we earn a small commission — affiliate relationship is disclosed.
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