Buy Follistatin 344 Research Protein

Follistatin 344 (FST344) is a recombinant human glycoprotein consisting of 344 amino acids, with an approximate molecular weight of 37,000 g/mol in its glycosylated form. It is the full-length isoform of Follistatin, first identified as a follicle-stimulating hormone (FSH) inhibiting factor in ovarian follicular fluid. FST344 contains three cysteine-rich Follistatin domains with EGF-like and Kazal-like motifs, an N-terminal atypical TGF-binding domain, and a highly acidic C-terminal tail. Produced via recombinant expression, Follistatin 344 functions as a high-affinity binding protein for multiple TGF-beta superfamily ligands including Activin and Myostatin (GDF-8).

Follistatin 344 is one of the most extensively investigated endogenous antagonists of the TGF-beta superfamily in preclinical research. Its capacity to bind and neutralize both Activin and Myostatin has established it as a key reference compound in studies examining the regulation of skeletal muscle mass, reproductive endocrinology, and tissue remodeling. In vitro studies in cell-based neutralization and receptor-binding preparations have characterized FST344’s binding stoichiometry and neutralization kinetics with Activin A and GDF-8, documenting comparable Activin-binding affinities across the FST isoform panel but markedly different cell-surface binding activity, with FST288 exhibiting the greatest cell-surface binding among the isoforms [2]. In vivo rodent studies have examined skeletal muscle phenotypes following Follistatin gene delivery in preclinical rodent models, documenting long-term increases in skeletal muscle mass and strength sustained for over two years in normal, dystrophic, and aged mouse models [1], making Follistatin 344 a key reference compound in multi-ligand antagonism research within the TGF-beta superfamily.

Follistatin 344 is produced to research-grade standards and independently verified by third-party HPLC and MS-UPLC analysis before dispatch. Vials are vacuum sealed and stored in a temperature controlled, monitored cold storage system. Certificates of Analysis are available to view and download directly on the product page.

Sold strictly for in vitro research purposes only. Not for human consumption. Intended for use by qualified researchers in laboratory settings only.

Scientific Review

Dr. Martina Rossi, PhD

Scientific Contributor and Reviewer

Reviewed for scientific accuracy, 14 June 2026

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