Informed-Sport Certified: Tested for banned substances, safe for athletes. 1,250 calories 50 g of protein 251 g of carbohydrates 25 vitamins and mineralsProduct Description Support your weight gain goals with OPTIMUM NUTRITION SERIOUS MASS The ultimate weight gain formula, ready to mix. Gaining serious weight requires serious calories. However, for many aspiring to get bigger, a fast metabolism, a smaller appetite, and a busy lifestyle can make it difficult to consume enough calories from whole foods alone. In such cases, Optimum Nutrition Serious Mass is the perfect supplement to a food-focused diet.