Follistatin
Also known as: follistatin 344, FST-344, follistatin-344, fst344
Follistatin is a human glycoprotein built from a 344 amino acid precursor, which is why the name follistatin 344 is common in research catalogs. It is studied mainly because it binds and neutralizes several TGF beta family signals, including activin and myostatin. UniProt catalogs the human protein under accession P19883.
Quick Reference
Follistatin - Research Images
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Overview
Mammalian protein found in Homo sapiens
Follistatin, also known as activin-bindings protein, is a protein that in humans is encoded by the FST gene. Follistatin is an autocrine glycoprotein that is expressed in nearly all tissues of higher animals.
Mechanism of Action
Follistatin works largely by catching TGF beta family ligands outside the cell and covering the site those ligands would use to attach to their type II receptors, which keeps the signal from starting. By neutralizing myostatin it removes a brake on muscle fiber formation, and separate work links it to SMAD3, AKT, and mTOR signaling. Inside the nucleus it can bind ribosomal DNA and slow ribosome production, a role tied to cellular energy balance.
Research History
Follistatin first drew attention as a pituitary factor that restrains follicle stimulating hormone release by capturing activin A. Later work widened its profile to muscle formation, nerve cell differentiation, and control of RNA production inside the nucleus.
What Researchers Are Saying
Community Reports - Not Medical Advice
The following is aggregated from public forums, Reddit, and research communities. These are anecdotal reports from researchers only - not verified clinical data and not a recommendation of any kind.
Follistatin (also known as follistatin 344, FST-344) is studied within the growth hormone axis and body composition research community. Glycoprotein that neutralizes myostatin and activin, studied for promoting muscle growth.
Last updated October 28, 2026
Research status: limited. Follistatin appears across growth hormone axis and body composition research forums and academic literature. Researchers note this compound falls in the growth hormone category.
Last updated October 28, 2026
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