PES Select Protein contains a combination of the highest quality milk protein isolate and whey protein concentrate 80% that will help build muscle. This formula contains whey protein and casein protein, which together result in a quick increase in protein synthesis along with a sustained elevation in plasma leucine levels. Plasma leucine levels are a key leader of muscle protein synthesis. The combination of whey and casein protein can help serve to maximize muscle protein accumulation. The blend of whey and casein protein will help you attain your goal of gaining more muscle and achieving a leaner body.