Follistatin 344 binds directly to myostatin, activin A, and other TGF-beta ligands with high affinity, preventing them from interacting with their type II receptors (ActRIIA and ActRIIB). By neutralizing myostatin signaling through the Smad2/3 pathway, follistatin is studied for its modulation of muscle protein synthesis and satellite cell proliferation pathways in preclinical and in-vitro models.
Research Use Only
Follistatin 344 — Myostatin Inhibitor for Muscle Research
A naturally occurring glycoprotein that binds and neutralizes myostatin, activin, and other TGF-beta superfamily members, studied for its role in muscle growth and tissue regeneration.
Muscle GrowthGrowth Hormone
~38 kDa • Prepared for research use • Per research workflow
Follistatin 344 Structure
Reference identifiers are batch-specific for coded materials and are documented on the lot COA/SDS rather than inferred or estimated.
Mechanism of Action
Follistatin 344 Overview
Follistatin 344 is a single-chain glycoprotein consisting of 344 amino acids that functions as a potent inhibitor of myostatin and activin — members of the transforming growth factor-beta (TGF-beta) superfamily. Myostatin is the primary negative regulator of skeletal muscle growth, and follistatin-mediated inhibition of myostatin signaling is studied at the receptor and pathway level in preclinical and in-vitro models, making it one of the most studied proteins in muscle biology research. Beyond myostatin inhibition, follistatin plays roles in reproductive physiology, inflammation, and tissue repair. It was originally identified in ovarian follicular fluid as a suppressor of follicle-stimulating hormone (FSH), from which it derives its name. Research has since revealed its expression in nearly all tissues, including liver, skin, and the vascular endothelium. The 344-amino-acid isoform (FS-344) is the precursor form that is post-translationally processed into FS-315 and FS-288, which differ in their heparin-binding affinity and tissue distribution. FS-344 is the most commonly used form in research due to its stability and broad activity profile. PharmaOrder supplies lyophilized Follistatin 344 with COA available for research applications.
Purity & Testing
Follistatin 344 is listed as 1mg. Catalog identity: molecular weight ~38 kDa. The lot COA for Follistatin 344 is available in your account. Finnrick Analytical performs HPLC purity analysis and mass spectrometry identity confirmation on that lot.
- Catalog configurations: 1mg
- Molecular weight: ~38 kDa
See the Follistatin 344 COA page.
Storage & Handling
Store the lyophilized powder at -20°C, protected from light; bring to room temperature before opening. For in-vitro preparation use an appropriate laboratory diluent.
Shipping
Ships worldwide from 6 distribution centers via USPS Ground Advantage
Available for direct research purchase
Research-use-only products are sold strictly for laboratory and research purposes. By purchasing, you acknowledge that these products are not intended for human or veterinary use, and you agree to PharmaOrder's RUO terms of service.
Published Research
Selected peer-reviewed studies referenced in this product overview.
Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member
McPherron AC, Lawler AM, Lee SJ. — Nature (1997)
Landmark study identifying myostatin as a negative regulator of muscle mass, establishing the rationale for follistatin-mediated myostatin inhibition.
Follistatin directly antagonizes activin function and blocks myostatin signaling through a novel mechanism
Lee SJ, McPherron AC. — Proceedings of the National Academy of Sciences (2001)
Demonstrated follistatin binds and neutralizes both activin and myostatin, producing dramatic muscle mass increases in transgenic mice.
Viral gene delivery of follistatin enhances muscle growth and strength in nonhuman primates
Kota J, Handy CR, Haidet AM, et al. — Science Translational Medicine (2009)
AAV-delivered follistatin increased muscle size, strength, and fiber diameter in nonhuman primates, demonstrating translational potential.
FAQ
What is Follistatin 344?
Follistatin 344 is a naturally occurring glycoprotein that binds and neutralizes myostatin, the primary negative regulator of muscle growth. It is the 344-amino-acid precursor isoform most commonly used in muscle biology and regenerative medicine research.
How does Follistatin inhibit myostatin?
Follistatin binds directly to myostatin with high affinity, preventing it from activating ActRIIB receptors on muscle cells. This removes the inhibitory Smad2/3 signaling that normally limits muscle protein synthesis and satellite cell proliferation.
How should Follistatin 344 be stored?
Store the lyophilized powder at -20 degrees C, protected from light, for long-term storage. Bring to room temperature before opening. For in-vitro preparation use an appropriate laboratory diluent. Follistatin is sensitive to repeated freeze-thaw cycles.
Editorial Review
Updated March 2026. Reviewed against product catalog, quality, and fulfillment standards. This page is educational and not instructions for human use. See our editorial standards and quality process.
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