Optimum Nutrition 100% Gold Standard CaseinFaster digesting protein is desirable immediately before and after exercise to Assist refuel recovering muscles, but slow digestion and absorption may be more beneficial at other times including bedtime when your body typically goes for hours without food. Casein products are acid sensitive and thicken in the stomach. Compared to some other proteins, it can take longer for our Gold standard 100% casein to be broken down into its amino acid