Optimum Nutrition Serious Mass: high-calorie gainer for hard gainers
Optimum Nutrition Serious Mass delivers 1263kcal, 50g protein, 251g carbohydrates and 5.5g fat per 334g serving. Protein sources are whey concentrate, calcium caseinate and egg albumin on a maltodextrin base, plus 3g creatine monohydrate and a full vitamin and mineral complex. The 5.4kg tub provides 16 full servings.
The three-source protein blend - whey concentrate for fast absorption, caseinate for sustained amino release and egg albumin for digestibility and leucine content - provides a fuller amino acid spread than a single-source mass gainer. Creatine monohydrate at 3g per serving contributes to physical performance in high-intensity exercise. At 1263kcal per serving, the formula is calibrated for hard gainers who need to add several hundred calories above their daily maintenance without sitting down to additional whole-food meals.
Serious Mass is one of the longest-running gainer formulas in the category - Optimum Nutrition has been producing it for decades precisely because it does what hard gainers need: it delivers calories reliably, mixes reasonably and provides a vitamin and mineral safety net alongside the macronutrients. There is no creatine-loading protocol, no complex timing requirement. Post-workout or between meals, one full serving fills the calorie gap that food alone cannot close for ectomorphic body types.
Built for naturally lean trainees, ectomorphs and anyone in a committed gaining phase who genuinely cannot eat enough whole food to move the scale. Not appropriate for people in a cutting phase, at maintenance or who gain fat readily - at 1263kcal per serving the calorie exposure is high and requires intentional training volume to utilise. Contains milk, egg, wheat and soy.
Alternatives: Applied Critical Mass Original 6kg (902kcal/59g protein) for a higher-protein gainer format, or XL Nutrition XTRA Mass Gainer 5.2kg (1000kcal/50g protein) as a comparable value-tier option.
