Optimum Nutrition Serious Mass is a high-calorie weight gainer designed to support muscle building and weight gain. Each serving provides up to 1,260 calories, 50 grams of whey protein concentrate, 250–253 grams of carbohydrates, and 5 grams of creatine monohydrate.
Additionally, it delivers 8 grams of naturally occurring glutamine and 11 grams of branched-chain amino acids (BCAAs) per serving. The formula also includes 19 essential vitamins and minerals to support overall health.
This product is ideal for individuals with high metabolic rates or those struggling to consume sufficient calories through whole foods alone. It is available in multiple flavors and is recommended to be mixed with cold water, milk, or another beverage for a rich and effective weight-gainer shake.