Optimum Nutrition Serious Mass is a high-calorie weight gain formula designed to help you build muscle and gain weight. Each serving provides 1,250 calories, 50 grams of blended protein, and over 250 grams of carbohydrates with no added sugar. It also includes 25 vitamins and essential minerals, creatine, glutamine, and glutamic acid to support muscle recovery and immune health. This vanilla-flavored protein powder is ideal for post-workout and between meals to help you achieve your fitness goals.