A person performing a pull-up exercise on a gym bar, focusing on strength training and muscle building

Shop by Product

Weight Gainers

Build muscle mass and gain weight with high quality calories from protein, carbohydrates and more.

Optimum Nutrition Gold Standard Pro Gainer, 5 lb container, vanilla custard flavor, supports muscle recovery and weight gain

Gold Standard Gainer

Protein & carb muscle recovery formula with 55 grams of protein and 109-116 grams of carbohydrates per serving.

SHOP NOW
Optimum Nutrition Serious Mass Weight Gainer, 2.73 kg container, supports muscle building and weight gain

Serious Mass

1,250 calories per serving to help boost calorie intake for muscle building & weight gain goals.

SHOP NOW

Customer Favorites

Optimum Nutrition Serious Mass supports , weight gain, muscle building, Banana flavor, 50g protein per servingOptimum Nutrition Serious Mass supports , weight gain, muscle building, Banana flavor, 50g protein per serving
Serious Mass
Sale priceFrom $30.99
Optimum Nutrition Gold Standard Pro Gainer, 10.19 lb bag, double chocolate flavor, supports muscle recovery and calorie intakeOptimum Nutrition Gold Standard Pro Gainer, 5 lb container, double chocolate flavor, supports muscle recovery and calorie intake
GOLD STANDARD® Pro Gainer
Sale priceFrom $76.99

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 2025 Edition, Sports Nutrition category, %retail value shares, 2024 data.
5. Not a low calorie food.
6. Naturally occurring amino acids.
7. See nutrition information for saturated fat, cholesterol and sodium content.