Follistatin
Follistatin is a glycoprotein that inhibits myostatin, the protein responsible for limiting muscle growth. By blocking myostatin, follistatin can theoretically allow for increased muscle development beyond natural limits.
Mechanism of Action
Binds to and neutralizes myostatin and activin, both of which are negative regulators of muscle mass. This removes the natural brake on muscle growth, allowing for enhanced hypertrophy.
Typical Dosage (Research)
Research protocols typically use 100-300mcg daily, though optimal dosing is not well established. Gene therapy approaches have also been studied.
Subcutaneous injection. Different isoforms exist (FS344, FS315) with varying properties. Requires careful sourcing due to complexity.
Side Effects & Risks
Limited human data. Theoretical concerns about effects on other organs where activin signaling is important.
Very limited human research. May affect reproductive function and other activin-dependent processes. Expensive and difficult to source.
Who Uses Follistatin
Researchers, advanced bodybuilders, those interested in myostatin inhibition.