ON Serious Mass 12lb Best Before 8-10/25

Vanilla Best Before August 2025

Chocolate & Strawberry Best Before October 2025

Free ON Gainer Shaker 

Every serve of Optimum Nutrition Serious Mass delivers over 1250 of nutrient loaded calories, that are blended with 50g of anabolic (muscle building) protein, from quality proteins such as ultra-filtered whey protein concentrate, calcium caseinate, and egg albumen.

Features:
+ Serious Weight Gain Protein Formula
+ 1,250 calories per serve
+ 50g Protein-High Protein
+ 25 Vitamins & Minerals Creatine & Glutamine
+ 250g of carbohydrates
+ No added Sugar
+ Muscle Building / Build Muscle
+ Strength Gains

Many athletes who are aiming to put on muscle size, tend to either have high metabolisms, weak appetites, or have on the run lifestyles, that make consuming sufficient calories through food alone, a challenge. Serious Mass provides 1250 calories per serve, which adds plenty of clean calories to a hard-gainers diet.

16 servings