My girlfriend and I recently became aware of the need to build muscle after 50, We had been using a protein powder that was working rather well but as we started a fasting cycle, it no longer worked for us. However when we discovered Advanced Amino, not only did it do what we were looking for, it started to work almost immediately. There isn't a day that goes but that we don't check in with each other how/if it's still working as excepted. After 2 months its working even better!