Optimum Nutrition Serious Mass
by Optimum Nutrition
"1250 calories and 50g protein per serving — the world's best-selling mass gainer with 25 vitamins and minerals"
Overview
Optimum Nutrition Serious Mass is the world's best-selling mass gainer with over 30,000 Amazon reviews. Each serving provides 1250 calories, 50g protein (from whey protein concentrate, calcium caseinate, and egg albumin), 252g carbohydrates, 25 vitamins and minerals, 5g creatine monohydrate, and 3g glutamine. The massive calorie count is designed for true hardgainers who struggle to eat enough whole food to gain weight. The Chocolate and Vanilla flavors are surprisingly good for a mass gainer, and the protein blend provides both fast (whey) and slow (casein) digestion.
Key Ingredients
| Ingredient | Amount |
|---|---|
| Multi-Source Protein Blend | 50 g |
| Calories | 1250 per serving |
| Carbohydrates | 252 g |
| Creatine Monohydrate | 5 g |
| Glutamine | 3 g |
Pros & Cons
What We Like
- 1250 calories (massive calorie boost)
- 50g protein per serving
- 30,000+ Amazon reviews (most popular mass gainer)
- 25 vitamins and minerals included
- 5g creatine included
What Could Be Better
- Only 8 servings per bag
- 252g carbs (very high sugar/carbs)
- Very thick when mixed
- Not suitable for cutting or weight management
Who Is This For?
Best For
- True hardgainers
- Extreme bulking phases
- Those who can't eat enough whole food
- Calorie surplus seekers
Not Ideal For
- Cutting phases
- Those watching carb/sugar intake
- Those wanting more servings per bag
- Moderate weight gain goals
Our Verdict
ON Serious Mass is the undisputed king of mass gainers — 30,000+ reviews, 1250 calories, and 50g protein per serving. The calorie count is extreme and designed for true hardgainers. For moderate weight gain, use half servings.