Whey powder is a common protein supplement made by dehydrating whey, the liquid by product of cheese production.
After the farmer receives milk from the cattle, the milk is refrigerated and pasteurized. After this process takes place, the milk can either be sold or it can be used to make cheese. A rennet agent is added to the milk to form curd. The whey protein is extracted from the curds by an ultra-filtration process to produce a dried protein powder. Both the fat and the lactose is removed to form the final product: whey protein. Therefore, individuals who have problems digesting lactose can usually take whey protein without any problems.