What Is Casein Protein?

Q: Why Take Casein Before Bed?

The argument: during sleep, you go 7-9 hours without eating. Muscle protein breakdown happens during fasted periods. A slow-release protein dose at bedtime keeps amino acids elevated through the night, blunting overnight breakdown and contributing to muscle protein synthesis through the early morning. The evidence backs this up. A 2012 study by Res et al. fed older men 40g casein before sleep and measured significantly higher overnight MPS compared to placebo. A 2015 follow-up by Snijders et al. extended this to a 12-week resistance training trial and found a casein-before-bed group gained measurably more muscle mass than the control group, even with identical total daily protein and training programs.

Q: How Much Casein at Bedtime?

The 2017 dose-response work from Maastricht University suggests: The standard recommendation is 30-40g of micellar casein within 30 minutes of sleep. Most commercial casein products serve 24-25g per scoop, so people commonly use 1.5 scoops at bedtime.

Question

What Is Casein Protein?

ProteinPrice Editorial · Accepted Answer

Casein is the slow-digesting milk protein that makes up about 80% of the protein in cow's milk. It forms a gel in the stomach that releases amino acids gradually over 6-8 hours, compared to whey's 90-minute spike. This makes casein the best protein choice for the longest gap between meals, especially overnight. The most common form on the market is micellar casein, which preserves the natural structure and slow-release behavior. Casein is not better or worse than whey: they serve different purposes.

What Is Casein Protein? (And Why People Drink It Before Bed)