Here are 7 reasons why your muscles stopped growing and how to get your muscle to grow again. 7. Alpha XTRM You do not eat sufficient protein - If you want to build bigger muscles, you must eat more protein. Protein is the building block for your muscles. It is recommended that you need 1 gram of protein per pound of your body weight equivalent. http://www.supplements4help.com/alpha-xtrm-scam/