For young guys lifting weights, eating 1.8 grams of protein per kilo of body weight each day is enough to gain muscle and get stronger in 10 weeks — it doesn’t matter if they take a 35g casein protein shake during the day or before bed.

If young, active guys lift weights 4 days a week and eat the same total amount of protein, it doesn’t matter whether they have their casein protein late at night or earlier in the day — they’ll gain similar muscle and strength over 10 weeks.

If young guys who lift weights drink a protein shake with 35 grams of casein every day — and keep training — they could gain about 2 to 2.8 kilos of muscle in 10 weeks.

If you're a young man who already lifts weights and eats enough protein, doing strength training twice a week for 12 weeks will make you stronger and build more muscle — and taking leucine supplements won't make any extra difference compared to taking a sugar pill.

If fit people already eat a lot of protein, taking extra casein protein in the morning or before bed doesn’t change their body fat or muscle over 8 weeks—if their workouts stay the same.

If guys who already lift weights drink a 20g protein shake after working out for 9 weeks, they’ll gain more muscle and get stronger—even if the protein is a mix of fast- and slow-digesting types.