Whey protein isolate is the purest form of whey available. Unlike whey concentrate whey isolate has had the fat and carbs from its milk source filtered out leaving you with what you want"straight protein to help you build muscle and change your body composition and no excess calories or sugar. Whey isolate not only contains all the essential amino acids that the body needs to build muscle its high in leucine"a branched-chain amino acid BCAA that signals muscle protein synthesis. Whey isolate has more leucine per gram than eggs milk or soy protein.