Follistatin 344

A glycoprotein that binds and neutralizes myostatin (GDF-8) and activin A, preventing them from engaging ActRIIB receptors and blocking the SMAD2/3 signaling that normally suppresses muscle growth.

Mechanism of action from published research — how the molecule behaves, not a claim about any product or any human-use effect.

Studied for muscle hypertrophy and muscle-wasting diseases (e.g., inclusion body myositis, Becker muscular dystrophy), primarily via gene-therapy delivery.

• Muscle & performanceStudied in muscle-growth, repair, and physical-performance research.

In clinical trials (gene-therapy form); early-phase human trials exist for inclusion body myositis/muscular dystrophy, but the injectable FS-344 protein sold in research contexts lacks human trial data of its own.

Where the science stands — an approved drug is not the same as the research-grade material a vendor sells, which is unregulated regardless.

• Independent purity. Look for a third-party COA (Janoshik or MZ) showing a measured purity — not just a number the vendor typed.
• Batch match. The strongest evidence is a certificate for the exact batch you’ll receive, attributed to this vendor — check the cross-verification on the listing.
• Vendor reputation. See how the vendor is talked about in the community before trusting a new name.

Research context only — VialGrade never gives dosing, medical, or human-use guidance.