Six Star Pro Nutrition Casein Protein delivers 24 grams of premium protein, including slow-digesting casein protein powder, which helps feed your muscles with a continued flow of amino acids (the building blocks of muscle). 100% of the casein protein component in Six Star Pro Nutrition Casein Protein is high-quality casein protein, which is a slow-release form of protein and is rich in amino acids. This makes it perfect to take between meals and before bed.