People take protein powders for lots of reasons – to balance out their diet, to help them lose weight, even as a general-health supplement. By far, however, the most common use for protein powders is to encourage muscle growth. But there are tons of different protein powders out there. So, which is the best protein powder for muscle gain? What should you look for? Consider the Source Protein powders can be made from all sorts of, sometimes unexpected, foods. Most typically, however, these supplements are created using either whey or casein – which are both taken from milk. Why does this matter? Because although the term “protein” as if there is just one type of protein, the truth is that the macronutrient can take on many, many forms. Proteins are made of much smaller compounds, called amino acids. Once inside your body, the proteins are broken down into these individual amino acids and these are then reorganized, restructured and repurposed – acting as the basic building blocks for just about every part of your body. When selecting the best protein powder for muscle gain, then, you want to be sure that you're getting all of the necessary amino acids. And this is one of the main reasons for the popularity of whey and casein – they are both complete proteins, providing all of the amino acids in high concentrations. Digestion But, once all of those amino acids are present in your body, it's important to make sure that they are keeping your muscle adequately fed. Simply put, some protein sources are easily absorbed to quickly to be properly used. Others aren't even completely broken down, offering very few actual muscle-building benefits. This is where casein really shines. Because of its unique chemical structure, casein clumps up when exposed to water, forming a sort of pudding. More specifically, this happens inside your digestive tract. Granted, that may sound unpleasant and somewhat useless. In truth, however, this is key to casein's muscle-building potential. That bundle of protein is slowly digested, feeding your muscles with needed amino acids over several hours. This trait is likely why casein is generally seen as being a superior muscle-building protein powder. Does that mean, however, that the fast-digesting whey is useless? No, not if used properly. There are specific times throughout the day wherein muscle protein synthesis – the process that uses protein to build muscle mass – is at its highest. Primarily, this is first thing in the morning, when you haven't eaten in several hours and shortly after your workouts. During these time-frames, a fast protein like whey will make sure that the amino acids are present exactly when they're needed the most. The Big Picture So, then, what is the best protein powder for muscle gain? Really, the answer is a combination of whey and casein. As we've already covered both of these milk-based proteins are loaded with all of the amino acids that your body needs to build muscle fibers, with some slight differences. The key variation, though, has to do with how the proteins are absorbed. Whey is give you a fast dose of protein when you need it most, while casein is more filling and works to keep you feed slowly over several hours. Read More: How Casein Protein Improves Cutting to Get Ripped How to Build Muscle Mass Using Weight Gainer Protein High Protein Breakfast Recipes