whey protein

Whey protein is a complete protein derived from milk (a by-product of cheese making) that supplies all the essential amino acids. The NIH Office of Dietary Supplements notes that whey contains more of the branched-chain amino acid leucine than either casein or soy. It is sold as a powder or in ready-to-drink products and is one of the most widely used sports-nutrition supplements.

According to the NIH Office of Dietary Supplements, adequate protein helps optimize the muscle response to training and the recovery that follows, and numerous clinical trials support adequate protein intake for building, maintaining, and repairing muscle. Importantly, this reflects the role of total protein intake rather than a unique effect of whey supplements specifically; protein from food works the same way, and MedlinePlus notes that most Americans already get enough protein from their diet. The ODS also indicates it is not clear from existing research whether consuming protein before versus after a workout makes a meaningful difference, and that supplements mainly help when it is hard to reach protein targets through food alone.

The NIH ODS lists a general protein intake for athletes of roughly 0.55 to 0.9 grams per pound of body weight per day (about 1.2 to 2.0 g/kg) from all sources combined — food plus any supplements — which the fact sheet illustrates as about 136 grams daily for a 150-pound person. A single serving of roughly 20-25 grams of a rapidly digested, leucine-rich protein around exercise is commonly studied. These are general figures, not personal medical advice; talk to a clinician or registered dietitian before starting, especially if you have kidney disease, a milk allergy, or other health conditions.

The NIH ODS reports no safety concerns at the recommended intakes for athletes of up to about 2.0 g/kg of body weight per day, with no known adverse effects for protein at these amounts, while also noting there is no benefit to consuming more than recommended amounts. Whey is made from milk, so it is not appropriate for people with a milk allergy and may cause symptoms in those who are lactose intolerant. As a general precaution, people with kidney disease, or who are pregnant or breastfeeding, should consult a clinician before using high-protein supplements.

At the recommended intakes for athletes, the NIH ODS reports no known adverse effects from protein. Because whey comes from milk, some people may experience digestive complaints such as bloating, gas, cramping, or diarrhea, particularly if they are lactose intolerant. As with any supplement, an allergic reaction is possible in those sensitive to milk proteins.

The NIH ODS fact sheet does not list specific drug interactions for protein at recommended athletic intakes. Because supplements are not tightly regulated and product quality varies, and because individual health conditions matter, tell your doctor or pharmacist about any whey protein product you use — especially if you take medications or have kidney concerns.