The ULTIMATE weight gain formula.
Add serious mass with 1,250 quality calories per shake.
Support muscle growth with 50 g of proteins and 250 g of carbs per serving.
Enjoy between meals, post-workout &/or before bed.

Optimum Nutrition’s Serious Mass is the ULTIMATE weight gain formula. If you find it difficult to gain weight, Serious Mass will help you develop the physique you've always wanted!

What Does It Do?
Each delicious shake delivers an incredible 1,250 calories, but no added sugar. This includes 50 g of blended protein to support muscle growth and 250 g of carbohydrates. Supports growth of lean muscle mass.

When Is The Best Time To Enjoy My Shake?
Simply mix up 2 scoops with milk or water in your Optimum Nutrition shaker and enjoy between meals, post-workout and/or before bed.