Serious Mass 5.44Kg “16 Servings” “Vanilla” Optimum Nutrition

One of the world’s best-selling weight gainers, Optimum Nutrition’s Serious Mass delivers over 1,250 calories per serving with 50g of blended protein. The 5.44Kg tub offers 16 servings of smooth Vanilla flavor. Fortified with vitamins, minerals, creatine, and glutamine, it’s the go-to formula for athletes who struggle to consume enough calories through whole food alone.