Optimum Nutrition Serious Mass Weight Gainer, 5.44 kg bag, and ON Micronised Creatine Powder container

The Original Mass Stack

  • Serious Mass (12lbs): 1,250 calories, 50g protein, 252-254g of carbohydrates per serving
  • Micronized Creatine Powder (300g): 5g pure creatine monohydrate per serving
  • Stackable products to easily optimize daily nutrition
Sale price$121.93 Regular price$135.48
Save $13.55

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1. These statements have not been evaluated by the food and drug administration. This product is not intended to diagnose, treat, cure or prevent any disease.
2. No significant difference has been shown between RBST treated and non-RBST treated cows.
3. When used over time in combination with regular resistance exercise.
4. Source Euromonitor International Limited; Consumer Health 2026 Edition, Sports Nutrition category, %retail value shares, 2025 data.
5. Not a low calorie food.
6. Naturally occurring amino acids.
7. See nutrition information for saturated fat, cholesterol and sodium content.