Casein Protein
Casein is the slow-digesting milk protein that makes up about 80 percent of the protein in cow's milk. It curdles in the stomach and releases amino acids gradually over 6 to 8 hours. Most people drink casein before bed to keep amino acids high overnight.
Why It Matters
Casein and whey come from the same source but behave very differently. Casein's slow release blunts overnight muscle protein breakdown, which is why nighttime casein has consistently outperformed placebo in muscle-gain studies. Casein is not a replacement for whey: it is a complement, useful specifically for long gaps without food.
How to Spot It on a Label
Look for micellar casein on the ingredient line: this is the slow-release form most people want. Calcium caseinate is a faster-digesting acid-precipitated form often used in bars and meal-replacements. Casein labels usually say 24 to 25g protein per scoop and recommend mixing with milk for a thicker shake.
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