Optimum Nutrition Serious Mass Weight Gainer

1,250 calories and 50 g of protein per shake.

Calories: 1,250
Protein: 50 g
Servings: 8 (6 lb)

Per serving, from the label. Formulas can change — always check the package.

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Deal updates for Serious Mass Weight Gainer

Why it's on our list

Serious Mass is the best-known mass gainer on the market, from the makers of Gold Standard Whey. Each two-scoop serving in water delivers 1,250 calories and 50 g of protein — a shortcut for hard gainers who struggle to eat enough food to grow.

2 scoops (336 g) per serving — 8 servings per 6 lb bag
Flavors: Chocolate, Vanilla, Strawberry, Banana, Chocolate Peanut Butter, Cookies & Cream
Made to be blended with milk, fruit or peanut butter for even more calories

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Questions people ask

How much protein is in one scoop of Optimum Nutrition Serious Mass Weight Gainer?

The number on this page comes from the Supplement Facts panel: protein per serving as printed on the label. Scoop sizes differ between brands (roughly 30–40 g of powder), so compare protein per serving and servings per container, not scoop counts.

Does protein powder expire?

Yes — every tub carries a best-by date, usually 12–24 months from manufacture. Powder keeps best sealed, dry and cool; once opened, use it within a few months and keep the scoop dry. Clumping or an off smell means it's past its best.

Protein powder or a protein bar?

Powder usually gives more protein per dollar and per calorie; bars win on convenience. Check the same two numbers on both: protein per serving and calories per serving.