Follistatin-344 (FST-344) is a 344-amino acid splice variant of follistatin, a naturally occurring glycoprotein that sequesters TGF-β superfamily ligands. FST-344 binds myostatin (GDF-8), activin A, activin B, BMP-2, BMP-7, and GDF-11 with high affinity, preventing their binding to ActRII and ActRIIB receptors. By antagonising myostatin signalling, FST-344 removes the primary endogenous brake on skeletal muscle mass. In murine models, FST-344 overexpression produces 2–3-fold increases in muscle mass. Distinguished from FST-288 (cell-surface bound) and FST-315 (predominant circulating form) by its heparin-binding domain.
Research Applications
Myostatin Inhibition
Primary GDF-8 antagonist for muscle hypertrophy model research
Sarcopenia
Age-related muscle loss models — ActRIIB pathway antagonism
GDF-8 Reference
Companion to recombinant myostatin (GDF-8) for receptor competition studies
BMP Modulation
BMP-2/7 sequestration for bone remodelling research
Muscle Wasting
Cancer cachexia and muscular dystrophy pathway research models
Follistatin-344 is a TGF-β superfamily ligand-binding glycoprotein that sequesters myostatin (GDF-8), activin A/B, and BMPs to block their ActRII/ActRIIB receptor signalling. In research models, FST-344 overexpression dramatically increases skeletal muscle mass by removing endogenous myostatin-mediated growth limits.
How is Follistatin 344 reconstituted?
Add 1–2mL bacteriostatic water to the lyophilized FST-344 vial. Follistatin is a large glycoprotein — dissolve slowly by directing water down the vial wall and swirling gently. Do not shake or vortex. Allow 5–10 minutes for full dissolution. Store at 2–8°C for 7–14 days.
What purity is QSC Follistatin 344?
QSC Follistatin-344 is ≥99% HPLC pure with MS-confirmed molecular identity on every batch. COA is published on the product page and verifiable at verify.janoshik.com.
Research Use Only: All QSC compounds are sold strictly for laboratory research purposes only. Not for human consumption, veterinary use, or any other application. Researchers are responsible for compliance with local regulations.
QSC Network
Compound reference, COA verification, and regional warehouse information across the QSC network.
