Whey Protein Isolates are *0% pure protein by weight. They are the purest and most expensive form of whey protein that exists. Thats why they are the first ingredients you read on the **0% Whey Gold Standard label. By using Whey Protein Isolates as our primary protein source, were able to pack *4 grams of the purest, muscle-building protein per serving, with a lot less of the fat, cholesterol, lactose, and other stuff that you can do without. Theres no question this is the standard by which other whey proteins are measured