Nutritional information may vary depending on flavour. What is Impact Micellar Casein? Impact Micellar Casein is our highly popular milk protein powder, designed to be slow-absorbing to provide a sustained supply of protein between meals and even while you sleep. This makes it the perfect choice for bedtime protein shakes, helping you to wake up raring to go, ready for your next session. It also includes a complete amino acid profile for a well-rounded formula. Performance Advisory Board Bringing together world-class scientists, doctors, and athletes to shape innovation at Myproteincombining cutting-edge research with real-world testing to create solutions that actually deliver, for everybody. Find out more about our Performance Advisory Board.