OnePin Peptide Library · Repair & Recovery
Follistatin 344
Follistatin · FST-344 · FS-344
Follistatin 344 (FST344) is a recombinant form of the naturally occurring glycoprotein follistatin, which is a potent endogenous inhibitor of activins, myostatin, and other members of the TGF-beta superfamily. The 344 designation refers to the full-length 344-amino-acid isoform, which is the precursor form that can be processed into shorter tissue-specific variants (FST315 and FST288). Follistatin plays a critical role in regulating muscle growth, reproductive physiology, and tissue repair.,Myostatin (GDF-8) is the primary negative regulator of skeletal muscle mass, and its inhibition by follistatin leads to dramatic muscle hypertrophy in animal models. Natural mutations in the myostatin gene or elevated follistatin expression have been documented in exceptionally muscular animals (Belgian Blue cattle, whippet dogs) and in one documented human case. This has driven interest in follistatin as a potential therapeutic for muscle-wasting conditions and as a performance-enhancing agent.,Follistatin 344 is currently a research compound with no regulatory approval for human use. Gene therapy approaches using follistatin (delivered via AAV vectors) have entered clinical trials for muscular dystrophies, including Becker muscular dystrophy and inclusion body myositis, conducted by Nationwide Children's Hospital. Injectable recombinant follistatin 344 used in the peptide community has not been studied in formal clinical trials and its pharmacokinetics, optimal dosing, and safety profile in humans are not well characterized.
Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.
How it works
Binds and neutralizes myostatin (GDF-8), activin A, and activin B with high affinity, preventing them from activating their type II receptors (ActRIIA/ActRIIB). By sequestering myostatin, follistatin removes the primary brake on skeletal muscle growth, allowing the Akt/mTOR hypertrophy pathway to proceed unchecked.,Modulates the activin-FSH axis in reproductive physiology. By binding activin, follistatin reduces FSH secretion from the anterior pituitary, which can affect gonadal function. This reproductive effect is an important consideration for off-label use.,May promote satellite cell activation and muscle regeneration by reducing TGF-beta superfamily signaling that normally inhibits myogenic differentiation. Also implicated in reducing fibrosis in damaged tissues by antagonizing activin-driven fibrotic pathways.
Binds and neutralizes myostatin (GDF-8), activin A, and activin B with high affinity, preventing them from activating their type II receptors (ActRIIA/ActRIIB). By sequestering myostatin, follistatin removes the primary brake on skeletal muscle growth, allowing the Akt/mTOR hypertrophy pathway to proceed unchecked.,Modulates the activin-FSH axis in reproductive physiology. By binding activin, follistatin reduces FSH secretion from the anterior pituitary, which can affect gonadal function. This reproductive effect is an important consideration for off-label use.,May promote satellite cell activation and muscle regeneration by reducing TGF-beta superfamily signaling that normally inhibits myogenic differentiation. Also implicated in reducing fibrosis in damaged tissues by antagonizing activin-driven fibrotic pathways.
What to expect
Days 1-7: Circulating myostatin is being bound by exogenous follistatin. No visible or subjective muscle changes expected in the first week.
Evidence
Interactions & stacking
What's safe to combine, and what belongs in a separate pin.
Safe & synergistic
Keep separate
Pharmacokinetics
Storage. Store refrigerated at 2-8C. Reconstituted solution should be used within 7-14 days. Avoid repeated freeze-thaw cycles. Sensitive to degradation.
Regulatory status
Research compound only. Not approved by the FDA or any regulatory agency for injectable human use. Gene therapy variants (AAV-follistatin) are in clinical trials for muscular dystrophies. Not a controlled substance but may violate anti-doping regulations (WADA prohibited list under gene doping/growth factors).
Put it to work
Calculate, log & track
Open Follistatin 344 straight into OnePin with your vial and dose pre-filled, then let it handle the syringe math and remind you before the vial runs out.
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The guide & community
The complete Follistatin 344 walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.
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