Mass Gainer Our most popular weight gainer formula designed for serious bulking, containing over 500kcal per serving including 66g of carbohydrate, 5g of leucine, & 40g of protein from slow & fast release sources. When it comes to building muscle, working out is only the first part. Your body needs protein to build new muscle, as protein contributes to the growth of muscle mass. So our Mass Gainer formula is loaded with a combination of protein from multiple sources, high quality carbs & added