Optimum Nutrition Serious Mass, Weight Gainer Protein Powder, Mass Gainer, Vitamin C and Zinc for Immune Support, Creatine, Chocolate Peanut Butter, 12 Pound (Packaging May Vary)
Condition: New
Buy Now, Pay Later
As low as
$12.17
/ mo
Learn more
- – 6-month term
- – No impact on credit to apply
- – Instant approval decision
- – Secure and straightforward checkout
Ready to go? Add this product to your cart and select a plan during checkout.
Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Apple Pay, and PayTomorrow. No-credit-needed leasing options through Acima may also be available at checkout.
Learn more about financing & leasing here.
Selected Option
Free shipping on this product
Non-returnable item
Learn more
Non-returnable due to Food safety reasons
View our full returns policy here.
Availability:
In Stock.
Arrives
Saturday, May 9
Flavor Name: Chocolate Peanut Butter
Size: 12 Pound (Pack of 1)
Features
- HIGH CALORIE WEIGHT GAINER: More than 1,200 calories per 2-scoop serving
- 50 grams of blended protein per 2-scoop serving
- 250 grams of carbohydrates per 2-scoop serving
- With over 20 vitamins and minerals including Vitamin C and Zinc to provide immune support
- MORE VERSATILITY: Using an electric blender, add fresh or frozen fruits, peanut butter, nuts, and other calorie dense foods to boost your weight gain potential
Description
More calories. More protein. More carbs. SERIOUS MASS by Optimum Nutrition serves over 1,200 calories, 50g of blended protein, and over 249g of carbohydrates per 2-scoop serving to help you maximize your daily caloric intake – the ideal post-workout and between meals shake for sizing up your goals. SERIOUS MASS provides you with more tools to help you pack on pounds, when taken in addition to normal calorie intake and over time with regular resistance training.
Brand: Optimum Nutrition
Flavor: Chocolate Peanut Butter
Servings per Container: 16
Item Weight: 12 Pounds
Material Type Free: Caffeine Free
Is Discontinued By Manufacturer : No
Product Dimensions : 11.5 x 5.5 x 16 inches; 12 Pounds
Item model number : 1056371
Date First Available : December 18, 2013
Manufacturer : Glanbia Performance Nutrition
Best Sellers Rank: #25,891 in Health & Household (See Top 100 in Health & Household) #20 in Sports Nutrition Weight Gainers #2,035 in Sales & Deals
#20 in Sports Nutrition Weight Gainers:
#2,035 in Sales & Deals:
Customer Reviews: 4.6 4.6 out of 5 stars (2,616)
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Saturday, May 9
This item is non-returnable:
Non-returnable due to Food safety reasons
View our full returns policy here.
Non-returnable due to Food safety reasons
View our full returns policy here.
- Klarna Financing
- Affirm Pay in 4
- Affirm Financing
- Afterpay Financing
- PayTomorrow Financing
- Financing through Apple Pay
Learn more about financing & leasing here.
Similar Products
Top Amazon Reviews
Serious Mass really lives up to its name. If you’re looking to put on size, this is one of the easiest ways to get a huge calorie and protein boost in one shake.. The taste is solid (I’ve tried Chocolate and Vanilla), though it’s definitely thick — I usually blend mine with milk or add a banana/peanut butter to make it smoother. It’s filling, so I don’t use it every day, but on heavy training days it’s perfect. The bag is big and lasts a while, though it can be a bit pricey. Overall, a great option if you’re serious about bulking and need extra calories.
...
show more
Reviewed in the United States on December 14, 2025 by Kara K
My most recent purchase from Amazon was the protein supplement, Optimum Nutrition Serious Mass. The reason I am writing this review (I usually don’t write reviews, unless the product is exceptional) is because I’ve found this product to be extremely helpful in my fitness goals. As a male in college, I don’t always have a lot of time on my hands. As you can imagine, college students often have varying and complicated schedules that require convenience and on-the-go products for our busy lives. But this product is definitely not only for college students but for people of all walks of life; people who need the right amount of nutrients and calories in a quick and convenient way that tailors to their schedule. I’ve been using this protein shake for quite some time now as this has been my fourth or fifth purchase. I wanted to wait for some time to see if this product does indeed have any positive effect on my fitness goals, so in short, Serious Mass by Optimum Nutrition does work. Who is this for? Serious Mass protein powder is for anyone looking to gain weight in a healthy, convenient, and safe way. It is for people who may need a boost in their weight due to their health situations, for lifters, bodybuilders, athletes, fitness enthusiasts and the list goes on. As for me, I am using this product to add on more weight when I go to the gym to lift and to increase muscle mass. Convenience Naturally, I have an extremely high metabolism. Since I am a hard gainer, to acquire more weight I need to eat a lot throughout the day. Because of time constraints and busy schedules, Serious Mass makes it easy to consume, essentially, a high-caloric meal. How much to use? The directions for this protein shake asks for a serving of two scoops; however, I have found this to be way too much as it is too chunky and thick even with the help of a blender. I suggest to use just one scoop as the scoop that’s included is very large with it being already about 625 calories. You can use this as a meal replacement but for optimal effect, this should be taken in between meals and before bed. Personal Experience I personally have found this extremely beneficial in gaining muscle. Within a couple of weeks to a month there are noticeable gains in muscle growth. As for taste, the protein powder actually tastes good unlike other brands; so far I’ve had strawberry and chocolate, both are very good. The only small issue that I have had with Serious Mass (along with all other protein powder supplements) is the need to use a bathroom relatively soon after consuming this product. As with many protein powder and supplements, it usually increases bowel movement. Then again it can be thought of as a small sacrifice to the greater benefits that are to come. Despite this review being quite lengthy, I truly hope that your goals will be met for whatever situation you try to achieve. As I have found this product very helpful; I hope that it too will benefit you all as well. Best wishes to your health and journey!
...
show more
Reviewed in the United States on September 18, 2016 by Amazon Customer
Love this mass gainer, it’s helped me gain weight through my fitness journey. Tastes good and isn’t hard to dissolve
Reviewed in the United States on November 12, 2025 by joel
The product did exactly what it promised. I started out weighing 185 lbs; today marks nearly a month since I started (26 days to be exact) and I'm weighing in at 201.9. I just worked out and took the last bit of the shake, therefore I believe I will be somewhere around 198-199 after it digests. The trick in this product is to stay consistent throughout the process. The serving size is ridiculous! I only took on scoop w/ milk after my workouts and/or one scoop in the morning (mostly on rest days). Also, one scoop every single night before bed. As much as I tried to talk myself out of a shake before bed some nights, it seems to be the only time that I truly feel it working its magic. The good: Chocolate Peanut Butter tastes great. It is a very thick shake; even with one scoop. Mixes easily as well. The bad: After a while the flavor gets overwhelming. It was really sweet to me and I started hating the idea of taking it. Luckily it goes down very quickly. Overall, the product worked. With my 15 pounds I gained mostly size and very little fat in my face and mid area. My abs still show and I don't look chunky but I still trained my abs like normal so I would expect them to show. As for the fat in my face, I believe I will lose it rather quickly naturally so I'm not too worried. Remember that this is a supplement and not a substitute so if at any time it is possible, still eat a nice meal for results. Trust me, if you are like me, you will get tired of eating. Especially with a stomach full of a thick shake but its worth it. I do not think that I will order another one at the moment. I am happy with the results and will strive to maintain my current size. I will go back to the Whey Protein from ON. However, I would recommend the product to anyone that is active and serious enough to be consistent with this powder. I may give it another try if I decide to gain a little more in the future.
...
show more
Reviewed in the United States on October 21, 2016 by Yodi
It helped, I am a very skinny guy in general, but I used it for months and worked out pretty regularly. I could see visible difference. Mix it with some milk it tastes so good. Never had any stomach issues like I normally do with other brands. Overall 10/10
Reviewed in the United States on November 14, 2025 by Shmök
My son’s favorite to put on weight! Dissolves easily! Great value!
Reviewed in the United States on December 8, 2025 by Melissa S.
great
Reviewed in the United States on December 30, 2025 by Victor Murillo
This is the best protein powder money can buy. If you’re someone who hates the grainy taste of generic protein powders, you will not have that with this. Tastes amazing. Been using it as a supplement for 8 years.
Reviewed in the United States on October 27, 2025 by Ken bone