Follistatin-344
A naturally occurring protein that inhibits myostatin and activin, promoting dramatic muscle growth.
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Compound Profile
Follistatin-344
Key Data
Research reference only
Research Focus
Preclinical data
⚠ Research & Educational Use Only. Follistatin-344 is a research chemical documented here for scientific education. All information references peer-reviewed literature and preclinical/clinical study data. Not for human consumption. Not medical advice. Consult a licensed researcher or healthcare professional before any laboratory use.
- Inhibits myostatin — removes the ceiling on muscle growth
- Dramatically increases muscle mass and strength
- Promotes satellite cell proliferation for muscle repair
- Follistatin-344 is not FDA-approved for human use. It is a research chemical for scientific study only.
Research At a Glance
- Inhibits myostatin — removes the ceiling on muscle growth
- Dramatically increases muscle mass and strength
- Promotes satellite cell proliferation for muscle repair
- Reduces body fat through metabolic effects
In Plain English
Simple summaryFollistatin-344 is a naturally occurring isoform of follistatin, a glycoprotein your body produces to bind and neutralize myostatin -- the protein that actively limits how much muscle you can build. Myostatin is essentially a biological governor on muscle growth; animals born without functioning myostatin develop dramatically enlarged muscles. Follistatin-344 is studied because it blocks myostatin and other members of the TGF-beta superfamily, potentially removing that governor. A single study in non-human primates (the Iskander 2006 paper) showed significant muscle mass gains after intramuscular injection of a follistatin gene therapy, which became widely cited in bodybuilding contexts despite being a gene therapy study, not a peptide injection study.
- Inhibits myostatin — removes the ceiling on muscle growth
- Dramatically increases muscle mass and strength
- Promotes satellite cell proliferation for muscle repair
The full scientific detail, mechanisms, citations, and dosing data, follows below.
What is Follistatin-344?
Tap any underlined term for an instant definition.
Follistatin-344 is a naturally occurring glycoprotein and one of the most potent muscle-building compounds studied. It works primarily by binding to and inhibiting myostatin (GDF-8) and activin, two proteins that act as negative regulators of muscle growth. By blocking myostatin, follistatin removes the body's natural brake on muscle hypertrophy, enabling significantly greater muscle growth than would otherwise be possible. Research in both animals and humans has shown remarkable results — in some gene therapy studies, subjects experienced 15–20% increases in muscle mass within weeks. It also plays roles in follicle-stimulating hormone regulation and neural development.
By the Numbers
Key Research Benefits
Documented effects observed in preclinical and clinical studies on Follistatin-344. See all Muscle & Performance peptides for comparison.
Common Stacks
Follistatin-344 is frequently combined with the following peptides for synergistic effects. Click any peptide to compare profiles before deciding.
Follistatin-344 removes the myostatin brake on muscle growth while IGF-1 LR3 provides the direct anabolic signal for hypertrophy and hyperplasia.
Follistatin-344 removes the myostatin brake on muscle growth while Ipamorelin provides the GH signal to drive anabolism.
CJC-1295 sustains elevated GH output, complementing Follistatin-344's removal of growth-limiting factors.
Side Effects & Risks
Adverse effects reported in the research literature. All data sourced from preclinical and clinical study reports. View all peptides' side effects →
Dosing Data from the Literature
Doses referenced below are sourced from published preclinical and clinical studies. Use the peptide dose calculator to convert these values to injection volume.
Research dosing: 100 mcg per day for 10 days (common protocol). More aggressive protocols use 300–500 mcg total over 5–7 days. Due to limited human research, caution is strongly advised. Not recommended for extended or repeated use without thorough understanding of risks.
Administration in Research Settings
Standard reconstitution and administration methodology for laboratory research use.
Reconstitute with bacteriostatic water. Intramuscular injection into target muscle groups may produce localized effects, while subcutaneous injection produces more systemic effects. Use the minimum effective dose. Long breaks between cycles are essential.
What the research doesn't show
The dramatic muscle-building results people cite almost always refer to the Iskander gene therapy study, where follistatin was delivered genetically to muscle cells -- a fundamentally different mechanism than injecting the peptide. Injected follistatin-344 has a short half-life and faces significant barriers to reaching muscle tissue at useful concentrations. The actual peptide injection literature is sparse. Managing expectations here is important.
Research Video
Medical Expert Videos
Physicians, researchers, and pharmacologists explain Follistatin-344, covering mechanisms of action, clinical context, and study findings.
Videos sourced from YouTube search. KnowYourPeptide does not endorse any individual creator. For research education only.
The Bottom Line
Follistatin-344 has a growing body of preclinical evidence and a well-characterised safety profile in research settings. The most-studied application is: inhibits myostatin — removes the ceiling on muscle growth.
The most commonly reported side effect in research subjects is limited human research — long-term safety profile not fully established. It is a research chemical, not approved for human use.
Frequently Asked Questions
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Quick Reference
How It Compares
Myostatin inhibitor antibodies (like anti-myostatin therapies in clinical development) are the pharmaceutical route to the same goal. ACE-031 (activin receptor fusion protein) blocks the same pathway more broadly. Follistatin-344 is a naturally occurring protein rather than a designed drug, which gives it different distribution and stability characteristics.
Compare Follistatin-344 side-by-sideResearch Use Only
This information is for educational research purposes only. This is not medical advice. Consult a qualified healthcare professional.