Follistatin-344

How it works

A 315-amino-acid protein that binds myostatin, the body's brake on muscle growth, sold in vials as a way to build mass.

What it's made of

A natural protein, not a short peptide. “344” is the number of amino acids in the precursor; once the exit signal is cut off, 315 remain. It traps myostatin, the signal that holds back muscle growth.

What it's for

Prescribed for

Nothing.

Sold as

Take the brakes off muscle: more mass by blocking myostatin.