Weider MEGA MASS 4000 has a high-quality protein blend from concentrated whey protein, casein, soy isolate and egg white. Mixing whey protein with casein optimizes uptake of amino acids from these proteins to minimize premature breakdown of amino acids caused by too rapid absorption. Weider™ MEGA MASS® 4000 delivers the high-quality calories and proteins you need to help you reach your optimal potential.