Gold standard 100% casein, slow-acting protein rapid protein use is desirable immediately before and after exercise to help refuel recovering muscles, but delayed digestion and absorption may be more beneficial at other times - including bedtime when your body typically goes for hours without food. casein proteins are acid sensitive and thicken in the stomach. Because of this, it can take more than twice as long for our gold standard 100% casein to be broken down into its amino acid subcomponents than other proteins. This premium micellar casein formula is truly time-released.