What is casein?
Casein makes up roughly 80% of the protein in milk, with whey making up the rest. Micellar casein, the least processed form, clots when it hits stomach acid. This slows digestion and releases amino acids over five to seven hours, compared with one to two hours for whey.
How it works
The slow, sustained release of amino acids gives a prolonged anti-catabolic effect across long fasting windows such as sleep. Casein is also highly satiating, which makes it useful for managing hunger in a calorie deficit.
What the research says
- 40g of casein before sleep increased overnight muscle protein synthesis (Res et al., 2012)
- Releases amino acids more slowly but for longer than whey
- Total daily protein intake matters more than timing for most people
- Its high satiety makes it a practical choice while cutting
Effective dose
20–40g per serve. The 40g dose is the one studied for boosting overnight muscle protein synthesis, commonly taken before bed.
What to check on the label
Look for micellar casein, the intact form, rather than calcium caseinate, which is more processed. Avoid blends padded with cheap fillers. Cottage cheese is an excellent wholefood source of casein.
Safety
Well tolerated by most people. Those who are lactose intolerant should take care, as micellar casein is low in lactose but not completely free of it.