Whey protein is a mixture of globular proteins isolated from whey, the liquid material created as a by-product of cheese production. During the cheese making process, the whey is often kept in a separate cheese vat so it can be utilized in supplements and other products. Some preclinical studies in rodents have suggested that whey protein may influence glutathione production and possess anti-inflammatory or anti-cancer properties; however, human data are lacking.
Whey protein is commonly marketed and ingested as a dietary supplement, most commonly in the form of whey protein powder. Various health claims have been attributed to it in the alternative medicine community. Whey is a common allergen, and is responsible for a significant proportion of cow milk allergies. In people without milk allergies, whey protein is generally considered safe.