Optimum Nutrition Casein 4lb Optimum Nutrition has come out with a Slow Digesting, Anti-Catabolic Casein Protein High in BCAAs! ON Casein Key Product Highlights: 24g of slow-digesting micellar casein per serving Over 5g of BCAAs (Leucine, Isoleucine & Valine) Very low levels of fat, sugars & carbohydrates 75% Protein by weight Ideal for use between meals and before bed Sometimes slower is better - especially when it comes to the rate of protein digestion. While rapid protein absorption is desirable directly before or after exercise, delayed release is probably more beneficial throughout the remainder of the day and night time. Casein proteins are pH sensitive and gel in the acidic environment of the stomach. As a result, it can take more than twice as long for caseins to be broken-down into their amino acid subcomponents than whey and other protein sources. Because of their unique time-released traits, caseins are aptly described as anti-catabolic or muscle-protecting proteins. Casein protein is ideal for use in between meals and before bed. Casein protein is sometimes known as "night time" protein because it's ideal to have just before you go to bed.