Casein is the main component of protein in milk that does not get into the whey .curd and cheese get their consistency from it. The casein proteins are responsible for storing and transporting the proteins into the body. Due to the special protein structure, it remains in the body for several hours, keeps the amino acid level in the blood constant and continuously supplies the muscles. This effect is called anti-catabolic (muscle-preserving). Overnight, the catabolic process sets in; by taking casein before going to bed, this process can be reduced.