The amount of protein in casein protein powder can vary depending on the brand and formulation. On average, casein protein powder typically contains around 20-30 grams of protein per serving. The protein content of casein protein powder can be even higher in some brands, with some products containing up to 90% protein. Casein is a slow-digesting protein source and is often used by athletes and bodybuilders as a night-time supplement to help maintain muscle mass and improve recovery while sleeping. It's best to check the specific product label for the exact protein content.