Soy Protein Isolate is a complete protein that is isolated from soy beans. Soy Protein Isolate is rich in BCAAs and 100% vegan. It is a complete protein that may help with muscle recovery after a strenuous workout. Protein is an important part of any diet, and it's vital in supporting overall health. Soy Protein Isolate is rich in BCAAs and 100% vegan. It is a complete protein that may help with muscle recovery after a strenuous workout.