Optimum Nutrition Serious Mass is a high-calorie weight gain formula designed to help you build muscle and gain weight. Each serving provides 1,260 calories, 50 grams of protein, and 252 grams of carbohydrates with no added sugar. It also includes 25 vitamins and minerals, creatine, glutamine, and MCTs. This protein powder is ideal for use between meals, after weight training, and before bed to support muscle recovery and growth. The chocolate-flavored powder is easy to mix with water or milk and can be enhanced with additional ingredients like fruits, nuts, and peanut butter for extra calories.