OPTIMUM NUTRITION SERIOUS MASS 12lb
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.
All orders placed before 2:00pm are packed same day and shipped to arrive typically the next working day. Please allow an extra 1-3 working days for driver delays.
We reserve the right to reject any order addressed to Great Barrier & Chatham Island, PO box or a Parcel Pod.
All non-rural orders over $50 within New Zealand include free shipping. For orders under $50, a flat rate of $3.99 is charged.
North Island - Next Business Day
South Island - 2-3 Business Days
Rural - +1 business days from the above times.
Rural - $4.99 surcharge applies. We suggest to send to a town or workplace that is not a rural delivery address.
Waikehe & Stewart Island - +1/2 business days from the above times ($9.98 surcharge applies. We suggest sending to a town or workplace that is in North/South Island)
Stewart Island - Items are delivered to the boatshed on the island, who phone receivers to collect the items from them.
Public holidays - NZ Couriers does not collect on Public Holidays, so there may be slight delays around these times.
Bay Supplements uses NZ Couriers within New Zealand.
If you have changed your mind after the courier has picked up your order, then you must organise for the return of the products for a refund. The goods must be returned to Bay Supplements within 7 days of the goods being received, and in an unused and unopened condition. If accepted the refund will be processed minus a restocking fee of $9.99. Unless the goods are faulty, the products will not be refunded or replaced if they are used and or opened. Return shipping for faulty goods will be covered by Bay Supplements. Return shipping for non-faulty goods will be covered by the customer.
NOTE; NO REFUNDS/EXCHANGE ON CLEARANCE ITEMS.