your born with it

"MY-OH-STAT-IN"

When you see your baby abs showing a little at that age and muscle on the back and arms. You will see that they have myostatin. When you don't see any. When they are one years old let them do one chin up and when they can they are myostatin.

Myostatin is the protein that is secreted to initiate growth. It effects the muscles because it inhibits muscle differentiation and growth.

Myostatin is a protein that is in the human body. It is specially encoded by the MSTN gene and is usually in the skeletal muscle cells to inhibit muscle growth and differentiation.