NutraBio Micellar Casein has a slow absorption rate into the bloodstream, which provides a steady stream of amino acids to muscle cells over 4-6 hours. This ensures positive nitrogen retention in muscles for much longer periods compared to whey protein. Casein is best taken at night or in combination with whey protein isolate after workouts to help provide sustained amino acid delivery during the two most crucial times of muscle growth: during sleep and post-training. NutraBio's Micellar Casein is a complete protein that supplies all of the essential amino acids in the amounts necessary for muscle growth and maintenance. Because of their unique time-released qualities, Caseins are considered anti-catabolic or muscle-protecting proteins.