Protein is separated into two key forms, whey and casein. Whey protein has skyrocketed in popularity thanks to the world of weight lifting and muscle building. Whey is a fast-digesting protein that is often mixed with liquid and taken immediately after working out. Casein, meanwhile, can take up to seven full hours to digest, meaning that as your muscles are recovering and re-growing following an intense resistance-training workout, casein protein is steadily feeding them with rebuilding fuel and helping prevent muscle breakdown.
Find a casein protein powder at your local fitness retailer. There are many options on the market; some are 100% casein, while others are a mix of casein with other ingredients. Some of these mixes contain lactose, so read each label carefully if you are lactose-intolerant.
Figure out your protein needs. If your goal is to gain muscle mass, your protein needs depend on your weight, according to research published in 2000 in the "Journal of the American College of Nutrition." Active individuals might need to eat 1.6 to 1.8 grams of protein daily per kilogram of body weight.
Determine when you're going to eat the casein. Casein can take up to seven hours to digest, and should be taken either before bed with your last meal, or at a time when you know you won’t be eating again for a while.
Decide what you're going to mix with the powder. Casein powder can be mixed with just about any kind of liquid — water, milk, or a custom shake you make in a blender.
Add the powder to the liquid and drink it. Make sure you read the instructions carefully and use the suggested serving amount. You can drink the liquid/casein combination before a meal, during a meal, after a meal or by itself.