Not all proteins are the same. At the apex of the pyramid is whey protein isolate (WPI), the primary protein source of P28. Made from whey protein that has been stripped of lactose, fat, and carbohydrates, WPI is the fastest-absorbing protein available. It consists of branched-chain amino acids, which are immediately used up by skeletal muscles during intense physical activity. They need to be replenished during and after exercise to optimize workouts and avoid fatigue. WPI also contains essential amino acids, making it a complete and superior protein for building muscles, losing weight, and getting healthy.