PEScience – Select Protein Select Protein is the pioneering protein of the whey + casein blend, shown to be more effective than 100% whey and uses premium milk protein isolate as the #1 ingredient. With all irresistible flavors developed in-house through our proprietary process, Select will be the first protein that you will actually crave every day. Carb friendly, low in fat and sugar, Select really is the best.