Hi, Welcome to HCM. Thanks for posting your query. Whey protein is the protein contained in whey which is nothing but the watery portion of milk that separates from the curds while making cheese. It is used for improving athletic performance, as a food supplement, as an alternative to milk for people with lactose intolerance. Whey protein is relatively proved safe for most children and adults when taken by mouth appropriately. Only in high doses it can cause some side effects such as increased bowel movements, nausea, thirst, bloating, cramps, reduced appetite, tiredness (fatigue), and headache. Only precaution needs to be taken is: If you are allergic to cow’s milk, avoid using whey protein. Hence, if taken in recommended doses, it appears to be safe.