Optimum Nutrition Gainers

Optimum Nutrition Gainers

Need help choosing the right gainer for your needs? Take a look at the bottom of the page where we've broken down each product.


Serious Mass is the ultimate in weight gain formulas. With 1,250 calories per serving and 50 grams of protein for muscle recovery support, this instantized powder makes the ideal post workout and between meals shake for sizing up your goals. Serious Mass provides you with the tools you need to pack on the pounds and help you develop the physique you’ve always wanted.

• 1250 Calories Per Serving (1,640 Calories If Mixed With Low-Fat Milk)
• 50g Protein Per Serve
• 252g Carbohydrate Per Serve (No Added Sugar)
• 5:1 Carbohydrate to Protein Ratio
• 25 Vitamins and Minerals Plus Creatine, Glutamine and Glutamic Acid
• Use Between Meals, Before Bed and/or Post-Workout



Gold Standard Gainer is built on a foundation of complete dairy proteins, mostly from isolate sources.
The carbohydrate blend includes oat, pea and potato and the fats include medium chain triglycerides, chia and flax. Obviously, this is not your typical gainer formula. ON took it a step further by making it easy to mix up in a shaker cup. No blender needed. This is the new Gold Standard for weight gain.

• 55g of Complete Proteins From Primarily Isolate Sources
• 770 Calories From Quality Ingredients
• 2:1 Ratio of Carbohydrates to Proteins
• 112g Complex Carbohydrates Oat, Pea & Potato
• 11g Fats From Flaxseed, Chia & MCTs
• Mixes Easily Into Cold Water or Milk
• Banned Substance Tested



Putting on size requires a balance of heavy training and quality nutrition. Because everyone's a little different, some have a harder time packing on muscle than others. PRO GainerTM is a high protein formula delivering calories that count during recovery. Each shake provides ample supplemental protein, carbs, vitamins and minerals to build on the amount you're getting through a balanced diet of food. Use PRO GainerTM as your post workout recovery shake and/or high protein meal between meals.

• 60 Grams of High Quality Protein
• 85 Grams of Carbohydrates to Help Restore Energy Levels
• High Protein to Carbohyrdate Ratio
• 24 Vitamins & Minerals
• 4-5 Grams of Dietary Fiber per Serving
• Ideal for Stacking with Other Size-Supporting Ingredients