What Is Follistatin? Benefits, Research & Safety

Follistatin was discovered in the late 1980s in ovarian follicular fluid, where it was found to suppress follicle-stimulating hormone (FSH) release from the pituitary—hence the name. Initial research focused on its reproductive endocrine functions. The discovery that follistatin bound to activins explained its FSH-suppressing effects, as activins are key regulators of FSH synthesis. This led to understanding of follistatin's broader role as an activin-binding protein. A pivotal discovery came with the identification that follistatin also binds to and inhibits myostatin. This was particularly exciting given the dramatic muscular hypertrophy seen in myostatin-deficient animals (like the Belgian Blue cattle and "mighty mice"). Research by Se-Jin Lee (who discovered myostatin) and others demonstrated that follistatin could promote muscle growth by inhibiting myostatin. This made follistatin an attractive target for conditions involving muscle wasting. Gene therapy approaches using viral vectors to deliver follistatin genes have been tested in muscular dystrophy patients, with some promising results. Jerry Mendell and colleagues at Nationwide Children's Hospital have conducted notable trials. Follistatin has also gained attention in the bodybuilding community, though the practical challenges of administering a complex glycoprotein and obtaining genuine product are significant.