Whey protein hydrolysate, commonly referred to as hydrolysate whey protein or whey peptide, is a type of whey protein that has gone through the hydrolysis process. When cheese is made from milk, the whey protein that results is a high-quality protein.

By using organisms or chemicals, hydrolysis breaks down proteins into smaller peptides and amino acids. The protein is predigested during this process, which facilitates absorption and utilisation by the body. In comparison to other types of whey protein, such as whey protein concentrate or isolate, hydrolysate whey protein is said to have higher digestion and quicker absorption.