Casein protein

Also known as micellar casein, caesin.

Last reviewed October 9, 2026 · Jump to references

What is Casein protein?

In plain words

Casein is one of the main proteins in milk. The body breaks it down relatively slowly into amino acids, the building blocks used to maintain and repair muscle and other tissues. Researchers study it for muscle maintenance, recovery after exercise, and feelings of fullness. It can cause allergic reactions in people with a milk protein allergy.

Technical definition

Casein is a family of milk phosphoproteins, principally αs1-, αs2-, β-, and κ-casein, that form micelles associated with calcium phosphate in bovine milk. Rather than acting through a single receptor, dietary casein is digested into peptides and amino acids that support protein synthesis; its tendency to coagulate in the stomach generally slows amino-acid delivery compared with whey. Casein is marketed as a food ingredient and dietary supplement, not as 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.