Supplement · Protein & amino acids
Casein protein
Also known as: Micellar casein
A slow-digesting dairy protein, popular before sleep, that helps you reach your protein target.
- Evidence
- Gold· human data
- Sources cited
- 1
- Last reviewed
- 22 July 2026
Casein is the slow-digesting fraction of milk protein, usually sold as minimally-processed micellar casein. It forms a gel in the stomach and releases amino acids gradually over several hours, which is why it is often taken before bed or between long gaps in eating.
What matters for muscle is hitting your total daily protein target; casein is a complete, high-quality way to do that, with good evidence for supporting muscle when intake would otherwise fall short. Its slow release is a modest, convenience-level advantage over whey rather than a decisive one: total daily protein does most of the work.