Protein can be a little like sex: Sometimes you want it fast; sometimes you want it slow; and sometimes a mix is even better. Casein is the fraction of milk protein that clumps after you consume it, delivering amino acids into your system more slowly and for longer periods of time. In other words, casein is a long romp compared with whey’s quick bang.
Casein protein continues to deliver amino acids for at least a couple of hours longer than whey protein when taken in equal supplemental doses (a little more than 20 grams). For this reason, it was once believed that taking casein was best as a meal replacement and also before bed.
More recent research, though, shows that a mix of casein and whey around workouts might be even more effective than either alone. While casein is still the best option before bed and other times when you want amino acids to last in your system longer, you can beneficially use casein around workouts, too. Just mix it with an equal portion of whey, or get in a whey-casein blend to help maximize muscle building.
Mixing and matching affords you different ways to take advantage of all casein’s benefits.