Stark Pharm's Flex GCM formula...
Casein is a slow-digesting milk protein compared to other proteins that digest quickly.
Optimum Nutrition - Gold Standard 100% Casein food supplement contains a high-quality, high-performance long-acting protein - micellar casein.
100% Casein Complex is a casein protein that is slowly digested, which provides a steady supply of amino acids to the bloodstream, possibly up to 7-8 hours.