Whey protein

Also known as whey isolate, whey concentrate, hydrolysed whey, whey protien.

Last reviewed October 9, 2026 · Jump to references

What is Whey protein?

In plain words

Whey protein comes from the liquid left when milk is made into cheese. Your body breaks it down into building blocks called amino acids, which help build and repair muscle and other tissues. Researchers study it for muscle strength and maintaining muscle as people age, particularly alongside resistance exercise. It can cause allergic reactions in people with milk allergies, and products containing lactose may cause digestive discomfort.

Technical definition

Whey protein is a mixture of milk-derived globular proteins, predominantly β-lactoglobulin and α-lactalbumin, recovered from the liquid fraction remaining after cheese production; commercial forms include concentrates, isolates, and hydrolysates. Digestion releases amino acids and small peptides, with leucine promoting muscle protein synthesis through mTORC1 signaling rather than whey acting at a single receptor. It is marketed as a food ingredient or dietary supplement, not an approved drug for treating disease.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.