The Mayo Clinic tested a combination of whey + casein protein which is found naturally in milk. What they found was that the two proteins work together to help build lean muscle.
100% whey protein can spike protein synthesis with the amino acid influx but then return to the baseline level where you started.
Casein protein, however, is slower digesting and typically consumed for its anti-catabolic properties because it releases amino acids over a much longer period of time. All in all, casein protein results in more protein retention than whey!
Researchers also found that the combination of whey and casein protein resulted in a quick increase in protein synthesis along with the sustained elevation in plasma leucine levels! Plasma leucine is the key in dictating muscle protein synthesis, and a combination of whey and casein proteins will help serve to maximize muscle protein accumulation. Consuming the fast-acting whey along with the slower digesting casein proteins together will help create the strongest leucine balance possible.
Select Protein is not complete without peptides.
Select Protein is a Three Phase Protein
Phase 1 is the pre-digested leucine peptides which help spike muscle protein synthesis.
Phase 2 is the whey protein to give the body more essential amino acids to aid in new muscle proteins. Both the pre-digested leucine peptides and the whey digest relatively quickly.
Phase 3 is the slower digesting casein protein, which helps protein synthesis continue around the clock!