SERIOUS MASS FOR SERIOUS MUSCLE. To gain weight, you need to consume more calories than you expend. For many aspiring to hit their calorie goals and put on size, a highly active metabolism, weak appetite or on-the-go lifestyle can make it a real challenge to get enough calories from food alone. SERIOUS MASS is the ultimate muscle building and weight gain formula. With 1,250 calories per 2-scoop serving and 50 grams of protein to support muscle recovery, this powder makes the ideal post-workout and between meals shake for sizing up your goals. SERIOUS MASS provides you with the tools you need to support your weight gains goals.