Description
Struggling to gain size? Optimum Nutrition Serious Mass is the ultimate weight gainer, packed with calories, protein, and carbs to help you put on size and strength. With over 1,250 calories per serve, plus added creatine, glutamine, and vitamins, it’s the smart way to hit your calorie surplus and fuel recovery. And because it’s Informed-Choice certified, every batch is tested for banned substances — safe for athletes and trusted worldwide.
Why Choose Serious Mass?
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1,250+ calories per serve – the easiest way to hit your calorie surplus.
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50g of protein – supports muscle repair and growth.
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250g+ of carbs – replenishes glycogen and drives recovery.
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Added creatine & glutamine – for strength, recovery, and immune support.
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25+ vitamins & minerals – helps cover daily nutrition needs.
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Informed-Choice certified – tested for banned substances, trusted by athletes.
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From Optimum Nutrition – the world’s #1 sports nutrition brand.
How to Use
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Mix 2 heaped scoops of Serious Mass with 700ml–1L of water or milk.
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Blend for best texture, add fruit, nut butter, or oats for extra calories.
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Take post-workout and/or between meals to increase daily calorie intake.
Pro tip: Start with half a serve if you’re new to mass gainers, then build up as your body adjusts.
Who’s It For?
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Hard gainers who struggle to put on weight.
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Athletes needing a high-calorie recovery shake.
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Busy professionals who can’t always eat enough during the day.
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Drug-tested athletes wanting a safe, certified weight gainer.
FAQ
Is Serious Mass safe for athletes?
Yes — it is Informed-Choice certified, meaning it’s tested for banned substances and manufactured in a registered facility.
How many servings per day should I take?
Most users take 1 serve daily, but you can increase to 2–3 smaller serves depending on calorie needs.
Can I use it as a meal replacement?
Yes — it’s calorie-dense with protein, carbs, and added nutrients, making it suitable as a high-calorie meal replacement.
Why Buy from Sprint Fit?
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100% authentic Optimum Nutrition supplements.
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Free NZ shipping on orders $60+.
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Same-day dispatch nationwide.
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Trusted by Kiwi athletes and fitness enthusiasts.
Optimum Nutrition Serious Mass – the ultimate weight gainer for size, strength, and recovery.
Facts
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.
FAQs
Optimum Nutrition Serious Mass Frequently Asked Questions
How many calories and grams of protein are in a serving of Serious Mass?
How many calories and grams of protein are in a serving of Serious Mass? Optimum Nutrition Serious Mass is a high-calorie weight-gainer engineered to support rapid size and muscle building. Each full 2-scoop serving delivers:
Calories: 1,250+ calories when mixed with water (significantly more when blended with dairy or plant-based milk).
Protein: 50g of premium protein blend (Whey Protein Concentrate, Calcium Caseinate, and Egg Albumen) to fuel muscle repair.
Carbohydrates: 250g+ of complex carbohydrates to replenish glycogen stores and drive recovery.
What performance ingredients are added to Serious Mass?
Beyond the massive macronutrient profile, each serving is enhanced with 3g of pure Creatine Monohydrate for strength and power, alongside L-Glutamine to support muscle recovery and immune function. It also contains a comprehensive blend of 25+ essential vitamins and minerals to fulfill daily nutritional requirements.
How many servings are in the 6lb and 12lb sizes?
Because the serving size required for 1,250 calories is a substantial 336g (2 large scoops), the breakdown across the available sizes is:
6lb (2.7kg) Tub: Contains 8 full servings.
12lb (5.44kg) Bag: Contains 16 full servings (offering the absolute best long-term value for a consistent calorie surplus).
How should a beginner use Serious Mass?
If you are new to high-calorie weight gainers, we highly recommend starting with half a serving daily (1 scoop) for the first week. This allows your digestive system to adapt to the nutrient density before gradually scaling up to a full 2-scoop serving.
Can Serious Mass be used as a meal replacement?
Yes. Due to its balanced blend of slow and fast-digesting proteins, complex carbohydrates, and essential micronutrients, it serves as an excellent, time-saving, high-calorie meal replacement for busy individuals and athletes who struggle to eat enough whole foods.
Is Optimum Nutrition Serious Mass safe for drug-tested competitive athletes?
Absolutely. Serious Mass is proudly Informed-Choice certified, meaning it undergoes regular, independent testing for banned substances. Elite sports players and competitive athletes across New Zealand can consume it with total peace of mind regarding label accuracy and safety.
What is the best way to mix Serious Mass?
Due to the sheer volume of powder, using an electric blender is highly recommended over a standard shaker bottle. Mix 2 scoops with 700ml to 1 Liter of cold water or milk, and blend for 45–60 seconds. Pro-tip: Add a banana, a spoonful of peanut butter, or oats to push your shake past 1,500 calories.
How fast is delivery for Serious Mass within New Zealand?
Sprint Fit offers super-fast nationwide shipping. Orders completed before 3:45 pm, Monday through Friday, qualify for same-day warehouse dispatch. Most North Island and Auckland orders land overnight, while South Island shipments generally arrive within 1 to 2 business days.
Shipping
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*
Click here to view the full Shipping Details and Returns Policy.
Often Bought Together
Optimum Nutrition Serious Mass Reviews
Chocolate
Quite nice tasting I got the chocolate one and far better than other chocolate protein shakes I've brought easy to mix with a Shaker and doesn't get clumpy isnt too thick too which I've found with othersChocolate
Love the taste. Very easy to drink. Have only just started taking it but weight has increased already. Recovering from knee surgery so muscle performance can't be rated yet.Chocolate
Thick and creamy, the way I like it. Shipping was super fast like myself.Chocolate
I bought the chocolate flavoured and I usually mix it with milk. It easy to blend and the taste is amazing!Chocolate
One of the best tasting Mass Gainers out there. Very good pricing and next day shipping.Chocolate
Banana
Optimum serious mass chocolate has to be my favorite protein, taste like a chocolate shake, thick as a shake and very filling. And you will put size and mass on with this. Banana is a bit sweet for me personally but definitely has the Banana hit Definitely recommend for anyone and will be back for my next order.Vanilla
Hands down the best price in the market. Never disappoints. Real talk.
