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Optimum Nutrition Serious Mass 5.45kg

Optimum Nutrition

  • The ULTIMATE weight gain formula.
  • Build your physique with 1,250 calories per shake, with no added sugar.
  • Repair & refuel: 50 g of proteins & 250 g of carbs.
  • Enjoy between meals, post-workout &/or before bed.
1250+ CALORIES 50G


ON’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 50g of blended protein to support building muscle and 250g of carbs to fuel your workouts.


When Is The Best Time To Enjoy My Shake?

Simply mix up 2 scoops with milk or water in your ON shaker and enjoy between meals, post-workout and/or before bed.

No surprise that customers voted Serious Mass ‘Weight Gainer of the Year’

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