Follistatin
FS-344 · FS-315 · Activin-binding protein
Think of it as a muscle growth accelerator.
Follistatin acts like a bouncer at a club, keeping certain proteins from blocking muscle growth. By telling myostatin to take a hike, it opens the doors for your muscles to grow bigger and stronger. Animal studies have shown some impressive gains in muscle size and strength when follistatin is involved.
In research settings, follistatin has been explored for its potential to help with muscle-wasting conditions, as it seems to encourage the body to pack on muscle. This has caught the eye of scientists looking for ways to tackle muscular dystrophy, though it's still under investigation and not approved for general human use.
Who it's for
- Bodybuilders looking to maximize muscle growth
- Athletes aiming to gain strength and size
- Fitness enthusiasts interested in cutting-edge muscle science
- Researchers studying muscle-wasting conditions
Probably not for you if…
- Casual gym-goers who aren't into experimental science
- Individuals looking for FDA-approved supplements
- People concerned about untested long-term effects
Editorial summary for research context · Not medical advice
Mechanism of Action
Follistatin is a naturally occurring secreted glycoprotein that binds and neutralizes members of the TGF-β superfamily, most notably myostatin (GDF-8) and activin. By sequestering myostatin, research suggests follistatin removes a major negative regulator of skeletal muscle mass. Preclinical gene-therapy and protein-delivery studies in rodents and primates show substantial increases in muscle size and strength. Follistatin is not FDA-approved for human use; clinical investigation has been limited to specific muscular dystrophy trials.
Researched Benefits
Myostatin neutralization
Animal studies demonstrate that follistatin overexpression leads to marked skeletal muscle hypertrophy via myostatin inhibition.
- [Lee & McPherron 2001]
Hypertrophy in primate models
AAV-follistatin gene delivery in non-human primates produced sustained muscle mass increases in preclinical trials.
- [Kota et al. 2009]
Explored in muscular dystrophy research
Early-phase trials have explored follistatin gene therapy for Duchenne and Becker muscular dystrophy.
- [Mendell et al. 2015]
Research Protocols
The following dosing ranges have appeared in published research protocols. Presented for informational purposes only — not a recommendation for human use.
Research investigational use
- Dosage
- 100 mcg
- Frequency
- once daily
- Timing
- morning
- Cycle
- 2 weeks
Research protocols using recombinant peptide forms have employed short cycles; human pharmacokinetics of injectable follistatin analogs are poorly characterized.
Reported Side Effects
- Injection-site irritation
- Theoretical disruption of activin signaling affecting reproductive and pituitary function
- Potential for disproportionate muscle growth exceeding tendon capacity in animal models
- Unknown cardiac hypertrophy risk with chronic exposure
- Long-term human safety data is absent
Contraindications
- Active or suspected malignancy (myostatin/activin pathways are implicated in tumor suppression in some tissues)
- Pregnancy and lactation
- Known cardiac hypertrophy or cardiomyopathy
- Pediatric populations
Stacking Partners
Peptides commonly paired with Follistatin in published research and protocol write-ups.
Vendor Pricing
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Gear + Companions
Reconstitution supplies and research-backed supplement companions for Follistatin. Editorial picks only — we earn a commission through Amazon on the click, no sponsorship.
Gear you'll need
· Reconstitution + storage essentialsBacteriostatic Water 30mL (0.9% Benzyl Alcohol)
Empower Pharmacy / generic medical supply
Reconstitutes every lyophilized peptide. 28-day viability refrigerated.
Insulin Syringes 31G × 5/16" × 0.5mL (100 count)
EasyTouch
31G × 0.5mL insulin syringes — the default size for sub-0.25mL peptide doses.
Alcohol Prep Pads (Sterile, 200 count)
Dynarex
Sterile 70% IPA prep pads — one per vial stopper + one per injection site.
1-Quart Sharps Disposal Container
BD / Becton Dickinson
FDA-cleared sharps container — pharmacies won't accept improvised disposal.
As an Amazon Associate we earn from qualifying purchases · Disclosed per FTC guidelines
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Research Papers
Regulation of myostatin activity and muscle growth
Lee SJ, McPherron AC · Proceedings of the National Academy of Sciences · 2001
PubMed 11459935 →Follistatin gene delivery enhances muscle growth and strength in nonhuman primates
Kota J, et al. · Science Translational Medicine · 2009
PubMed 20371490 →