Muscle is built bigger and stronger during recovery, a process requiring rest and amino acids from protein. While many weight training adults know how a rapidly digesting post-workout protein shake can help kick-start the recovery process, not nearly as many have first-hand experience with slowly digesting protein shakes used right before bed. A study published in the journal Medicine & Science in Sports & Exercisetested bedtime casein shakes on 16 healthy young men.

An hour after a session of weight training that ended at 8 PM, subjects received a shake containing 20 grams of protein and 60 grams of carbohydrates. Before hitting the sack at 11:30 PM, some got 40 grams of casein protein while the rest received a placebo. Blood samples and muscle biopsies showed that casein elevated circulating amino acid levels and increased whole body rates of protein synthesis, improving net protein balance.

True Strength Moment: Protein synthesis was 22% higher for casein users versus placebo. Since recovery from weight training can take up to 48 hours to complete, keeping the aminos coming in your sleep seems like it might help support the goals of active adults working hard to increase muscle size and strength.