Myostatin is the greatest single catabolic-limiting factor of extreme muscle growth, athletic performance, and aging. In short, myostatin exists in our bodies and basically works to limit muscle growth, muscle tone, strength, and body shape. Basically, too much myostatin and your muscle mass shrinks, your fat deposits grow, your strength disappears, and your body becomes formless. Similarly, a clinically significant reduction in blood myostatin levels may unchain the shackles that limit your potential to build muscles and develop.