Whey protein isolates are 90 percent pure protein by weight. They are the purest and most expensive form of whey protein that exists. That’s why they are the first ingredients you read on the 100 percent Whey Gold Standard label. By using whey protein isolates as the primary protein source, it’s possible to pack 24 grams of the purest, muscle-building protein into each serving, with a lot less of the fat, cholesterol, lactose and other stuff that you can do without. There’s no question this is the standard by which other whey proteins are measured.