Serious Mass by Optimum Nutrition is a 5.45 kg gainer designed for those needing a high calorie intake to gain muscle mass. Each serving of 2 scoops offers 50 g of protein, 1260 calories, 251 g of complex carbohydrates, 5 g of creatine monohydrate, 8 g of glutamine, and 24 g of essential amino acids, along with a complex of 25 vitamins and minerals. Ideal for individuals looking to elevate their daily protein and calorie intake, or for those struggling to gain weight due to a fast metabolism. The protein is primarily derived from whey protein concentrate, supplemented with calcium caseinate and egg albumin, ensuring a sustained release of amino acids. This supplement comes in a 5.45 kg package and is available in various flavors. It is recommended to mix 2 heaping scoops (340 g) with 700 ml of water, milk, or another beverage. Store in a cool, dry place, protected from direct sunlight, and close the container tightly after each use.