Optimum Nutrition Serious Mass is the ultimate weight gain and muscle-building formula designed for hardgainers, athletes, and individuals struggling to hit their daily caloric targets. Packing a massive 1,250 calories and 50 grams of quality protein per serving, this high-calorie gainer provides the raw firepower needed to support heavy resistance training, promote serious muscle hypertrophy, and break through stubborn weight plateaus.

Key Benefits & Features

• Massive Caloric Density: Delivers 1,250 calories per serving (when mixed with water) to make hitting extreme calorie surpluses effortless.

• High-Protein Muscle Support: Features 50g of blended protein from whey, casein, and egg sources to support muscle repair and sustained growth.

• Complex Carbohydrate Fuel: Packed with 250g+ of carbohydrates without added sugar to replenish glycogen stores and power intense gym sessions.

• Fortified with Creatine & Glutamine: Contains added Creatine Monohydrate, L-Glutamine, and Glutamine Peptides to maximize muscle strength, power, and cell recovery.

• Comprehensive Vitamin & Mineral Blend: Enhanced with 25 essential vitamins and minerals to support daily health, metabolism, and immune resilience.

How It Works

Serious Mass works by supplying a dense, highly absorbable stream of macronutrients and micronutrients that fuel anabolic muscle growth. The protein blend combines rapid, moderate, and slow-digesting protein sources (whey protein isolate/concentrate, calcium caseinate, and egg albumen). This multi-stage release delivers a sustained flow of essential amino acids into your bloodstream, keeping your body in an anabolic (muscle-building) state for hours.

The complex carbohydrate matrix rapidly restores depleted muscle glycogen levels following high-intensity training, preventing your body from burning hard-earned muscle for fuel. Additionally, the inclusion of Creatine Monohydrate helps restore ATP reserves for explosive strength, while the full spectrum of vitamins and minerals ensures efficient nutrient metabolism and cellular health.

Recommended Use

Mix 2 heaping scoops (334g) with 700ml of cold water, whole milk, or your favorite beverage in a Sprint Fit shaker or blender. Blend for 45–60 seconds until smooth. Beginners may prefer starting with a half serving (1 scoop) daily and gradually increasing to a full serving. Consume between meals, post-workout, or before bed to meet your daily caloric requirements.

Available Sizes:
Container Size: 2.7KG (6Lb)
Serving Size: 2 Scoop (336g)
Servings Per Container:8

Container Size: 5.44KG (12Lb)
Serving Size: 2 Scoop (336g)
Servings Per Container: 16

Please Note: Nutritional Information is to be used as a guide only, actual values may differ between flavours and sizes and when formulations are modified or updated by the manufacturer. 
Contact us if you have any questions regarding this products ingredients.

All orders $60 and over receive Free* Shipping Nationwide 

Final pick up each day is at 3.45pm Monday to Friday. 

Estimated Delivery Times*:

Auckland and North Island – Overnight

*During sale periods, please allow an additional 1–2 business days for dispatch due to high order volumes.

However many Auckland orders will be delivered the same day depending on what time the order is placed

South Island – Overnight (For larger parcels allow 2 business days)

Same Day/Evening Express Shipping upgrade available at checkout for select suburbs*

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