Follistatin

Follistatin is a single-chain glycoprotein that functions as a potent binding protein for activins and myostatin (GDF-8). It is studied in research settings for its role in modulating TGF-β superfamily signaling, with particular interest in its effects on skeletal muscle and reproductive biology pathways.

Follistatin is a glycoprotein that binds and neutralizes activins and myostatin, key members of the TGF-β superfamily. It is studied in laboratory research for its modulatory effects on muscle biology, reproductive signaling, and fibrotic pathways. Supplied as a lyophilized research protein.

Follistatin was first identified in the late 1980s from porcine follicular fluid as an FSH-suppressing protein. Subsequent research revealed its broader role as an activin-binding protein with high affinity for myostatin. Multiple isoforms (FS288, FS303, FS315) have been characterized, each with distinct tissue distribution and binding properties.

Published research has demonstrated that follistatin binds and neutralizes activin A, activin B, and myostatin with high affinity, modulating their downstream signaling through Smad pathways. Animal studies have shown that follistatin overexpression or administration produces measurable changes in skeletal muscle mass parameters. Research also examines its role in reproductive endocrinology and fibrosis models.