Myostatin
Also known as: Myostatin, GDF-8 Inhibitor
Myostatin (GDF-8) is a naturally occurring protein that limits skeletal muscle growth. In the research and peptide market the term commonly refers to myostatin-inhibitor compounds intended to block this growth-limiting signal. Note: Myostatin (GDF-8) is a protein that LIMITS muscle growth; research interest centers on inhibiting it, not administering it.
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Mechanism of Action
Myostatin is a TGF-beta superfamily member secreted by muscle that binds the activin type IIB receptor (ActRIIB), recruiting ALK4/ALK5 type I receptors and phosphorylating SMAD2/3 to suppress myoblast proliferation and muscle fiber hypertrophy. Loss of functional myostatin, as seen in certain double-muscled animal phenotypes, produces dramatic muscle overgrowth. Myostatin-inhibitor research compounds aim to antagonize the ligand or its receptor, releasing the SMAD-mediated brake and allowing increased muscle protein synthesis and satellite-cell activity.
- Half-life
- Varies by inhibitor format; small-molecule and peptide forms range from hours to days
- Administration Routes
- subcutaneous
- Research Status
- Research Chemical
Reported Benefits
- Inhibiting myostatin signaling can increase muscle fiber size in models
- Studied for counteracting muscle wasting and atrophy
- May support strength and lean-mass gains in research settings
- Investigated as an androgen-free approach to muscle preservation
- Relevant to research on metabolic improvement via greater muscle mass
Potential Side Effects
- Potential tendon and connective-tissue strain with rapid muscle change
- Injection-site irritation
- Possible effects on other TGF-beta-regulated tissues
- Sparse human safety data
Common Dosing
There is no standardized protocol; research preparations marketed as myostatin inhibitors are dosed per supplier guidance only. Provided for research and educational reference only, not as personal medical advice.
The dosing information above is aggregated from research literature and anecdotal community reports for educational purposes only. It is not a recommendation, prescription, or medical advice. Peptides are sold as research chemicals only and are not intended for human use.
Contraindications
- Pregnancy and breastfeeding
- Active malignancy without specialist oversight
- Pre-existing tendon or joint instability
Follistatin 344
Follistatin 344 is the full-length precursor isoform of follistatin studied for blocking myostatin and activin to drive muscle growth and tissue repair.
Follistatin 315
Follistatin 315 is the circulating isoform of follistatin, a myostatin-binding protein studied for promoting muscle growth by removing the brake on muscle development.
ACE-031
ACE-031 is a soluble decoy receptor (ActRIIB-Fc fusion) studied as a myostatin inhibitor to increase muscle mass and strength.
Trevogrumab
Trevogrumab (REGN1033) is an investigational fully human monoclonal antibody that binds and neutralizes myostatin (GDF-8). It has been studied as an anti-myostatin therapy aimed at preserving or increasing skeletal muscle mass. Note: Trevogrumab is a monoclonal antibody (anti-myostatin), not a peptide; included here for reference.
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Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member
1997
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Myostatin mutation associated with gross muscle hypertrophy in a child
2004
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Myostatin: A Skeletal Muscle Chalone
2023
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Myostatin antibody (LY2495655) in older weak fallers: a proof-of-concept, randomised, phase 2 trial
2015