Optimum Nutrition Serious Mass is a high-calorie weight gain formula designed to support muscle building and fuel intense workouts. Each serving delivers up to 1,250 calories, 50 grams of protein, up to 254 grams of carbohydrates, and 5 grams of creatine monohydrate. This mass gainer formula is specifically crafted for athletes with ambitious muscle and performance goals, providing essential carbohydrates for energy and calories to support a bulking diet. The protein source is fast-digesting whey protein concentrate, ensuring efficient muscle recovery. Additionally, this muscle gainer supplement includes 19 vitamins and minerals, along with 8 grams of naturally occurring glutamine per serving. With its impressive nutrient profile, Optimum Nutrition Serious Mass is the ideal choice for those looking to enhance their weight gain and muscle building efforts.