Whey protein gives you a quick spike in amino acids in your blood, while casein keeps levels up longer — but overall, they give your body about the same amount of fuel, and neither one boosts muscle...

If young, healthy guys drink a protein shake before bed after working out, it doesn’t matter if it’s whey or casein—both help their muscles recover just the same overnight.

Drinking 45g of either whey or casein protein before bed helps muscle recovery just as much after endurance exercise in young, healthy guys — neither one works better than the other.

When older guys drink a whey or pre-digested casein protein shake, the protein shows up in their blood faster than when they drink regular casein — meaning it gets absorbed more quickly.

For female college athletes who lift weights, taking 24 grams of whey or casein protein before and after workouts for eight weeks leads to the same results in muscle, strength, and performance — so both types work just as well.

If a young guy drinks a protein shake with a mix of whey and casein, his body absorbs the important amino acids about as well as with pure whey—and better than with pure casein—over the next 6 hours.