The two most common forms of whey powder are "isolates" and "concentrates" and the type you choose makes the difference between an average supplement and a superior one. Those in the industry understand that isolates are the superior protein. Whey concentrates contain less protein and more ingredients that are not desirable, like lactose and fat. The cleaner profile in isolates are more conducive for adding muscle and losing weight. Not all isolates are the same. Please take heed to other isolates on the market loaded with artificial sweeteners, such as sucralose.