Optimum Nutrition Serious Mass

ON Serious Mass is a high-calorie weight gainer delivering 1,250 calories, 50g of protein, and over 250g of carbs per serving. Formulated with creatine and 25 vitamins, it’s designed specifically for "hard gainers" to pack on significant muscle mass and size.

Mix 340g (about two heaping scoops) with cold water, milk, or other beverage in blender for 30-45 seconds until dissolved.
New users may find it beneficial to begin with half of a serving for the first week and then gradually increase to 1 serving.
Suggested Use: For best results, consume 2-scoop serving regularly over time in combination with regular resistance exercise.