If you are serious about building lean, strong muscle, Sci-MX's flagship protein product is a must! GRS-5 Protein System is a new generation, scientifically formulated protein drink designed to supply a sustained release of proteins for longer periods that ordinary protein. When subjected to weight or conditioning training, muscles grow in size and strength more effectively if constantly supplied with amino acids over a gradual period. Immediately after exercise, muscles require rapidly metabolised proteins like whey protein isolate and concentrate. GRS-5 contains optimum quantities of both. For the periods in between training sessions, meal times and during sleep, muscles continue to repair themselves, and this is when gradually absorbed proteins are best. So in addition to whey protein, GRS-5 also contains gradually released proteins from milk, egg white and soy which together with work in synergy with a complex enzyme package called OptiZyme, which increases the uptake of BCAA's (branch chained amino acids) and free form amino acids.