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🚀 Bulk up like a boss with Serious Mass — because average gains are so last season!
Optimum Nutrition Serious Mass is a high-calorie weight gainer delivering over 1,200 calories, 50g of blended whey protein, and 249g of carbs per 2-scoop serving. Enhanced with 20+ vitamins and minerals including Vitamin C and Zinc for immune support, plus creatine for muscle performance, it’s designed for adults aiming to bulk up efficiently. Ideal for post-workout or between meals, this chocolate-flavored powder blends best with a blender and offers versatile mix-in options to maximize your calorie intake and muscle growth.






















| ASIN | B0015R36SK |
| Age Range Description | Adult |
| Allergen Information | Milk, Soy |
| Best Sellers Rank | #1,912 in Health & Household ( See Top 100 in Health & Household ) #2 in Sports Nutrition Weight Gainers #241 in Sales & Deals |
| Brand | Optimum Nutrition |
| Brand Name | Optimum Nutrition |
| Customer Reviews | 4.5 out of 5 stars 32,625 Reviews |
| Diet Type | Vegetarian |
| Flavor | Chocolate |
| Item Dimensions | 6.14 x 6.14 x 9.76 inches |
| Item Weight | 0.9 Kilograms |
| Manufacturer | Glanbia Performance Nutrition |
| Manufacturer Part Number | 1101537 |
| Material Type Free | Caffeine Free |
| Model Name | ON SERIOUS MASS CHOCOLATE 6LB |
| Model Number | 1101537 |
| Number of Items | 1 |
| Package Type Name | Tub |
| Product Benefits | Immune Support, Muscle Growth, Weight Gain |
| Protein | 50 Grams |
| Protein Source | Whey |
| Recommended Uses For Product | Calorie Increase, Muscle Growth, Post-Workout, Weight Gain |
| Servings per Container | 8 |
| Supplement Formulation | Multi-Supplement |
| Total Servings Per Container | 8 |
| UPC | 748927022995 |
| Unit Count | 96.0 Ounce |
| Vitamins And Minerals | 0.9, 3.7, 30, 5, 700 Milligrams, 410, 80 Milligrams |
K**S
It helps a lot
Optimum Nutrition Serious Mass is a great choice for anyone looking to gain weight, build muscle, or increase overall calorie intake. The Chocolate flavor mixes smoothly—especially if you use a blender—and has a rich, dessert-like taste without being overly sweet. Each serving delivers a very high amount of calories, protein, and carbs, which makes it ideal for people with fast metabolisms or those who struggle to eat enough throughout the day. It also includes added vitamins, minerals, and creatine for extra support. The bag is large and lasts a good amount of time depending on how much you use. The powder is heavy, so mixing by hand can be a bit difficult, but blending solves that problem easily. Overall, Serious Mass is effective for healthy weight gain and muscle-building goals. If you need a calorie boost and don’t mind a thick shake, it’s a solid and reliable product.
D**D
Chocolate
ChocolateSize: 12 Pound (Pack of 1) Optimum Nutrition Serious Mass is a great choice for anyone looking to gain weight, build muscle, or increase overall calorie intake. The Chocolate flavor mixes smoothly—especially if you use a blender—and has a rich, dessert-like taste without being overly
R**S
Awesome protein shake brand!
Love this product. I get sick to where I cant eat this helps me pull back the calories and rebuild my muscles quickly so I dont lose my progress. The taste is good and milky doesn't have soy (which im allergic to) which most proteins contain. There is a chocolate smell that is very pleasant. It dissolves without having to be blended and blends well in my shaker bottle.
M**G
Like I said 1250 calories per serving and that is ...
I work for the USPS so I walk miles and miles a day. Making it hard for me to gain or maintain a healthy weight. I eat a lot but my metabolism its too fast for me to keep up with it too. Here is what I think about this protein powder. 1. It makes you gain weight. I took it for a week every day before bed and gained from 5lbs in almost 2 weeks. I did have to mix it with other stuff just to bump up the calories count. Note that it says 1250 calories per serving that means 2 scoops of protein powder and the scoop is huge as it is. It is kind of hard to include other things other than milk because each serving has so much protein powder already that sometimes you end up with a huge huge protein shake. 2. What's in ever scoop? Whey protein, casein, vitamins, minerals, and essential fatty acids to help you pack on the pounds without gaining fat. It also delivers 1000 mg of creatine monohydrate (a nitrogenous organic acid that supplies muscles with essential fuel). Like I said 1250 calories per serving and that is if you mix it with water. If you chose milk its about 1650 calories per serving, but it varies depending on what kind of milk you prefer. 3. How does it taste... the taste is a very super rich and thick chocolate taste. I don't know how to describe it, but the taste is delicious I promise. The only reason why I didn't rate this product with 5 stars its because it kind of gets a little pricing since each package has only 16 servings. For me it works because as soon as I gain my desire weight its easy for me to keep up with it by just drinking half of the serving size once a week. Another thing that I didn't like is the bag is huge and hard to storage or to move around. I had to split mine into 3 parts. What bother me the most is the texture and form of the powder. It's very thin almost like dust (not really, but kind of). Every time I try to make a shake the powder gets all over the place because the scoop is so big for my ninja blender. So it does get messy have fun trying to make a shake right before work without getting it on your clothes or without making a mess.
K**S
Great price & product.
Great price! Fantastic product. My husband is 63 and started using up his muscle mass. This works perfectly in his routine. He is a hard working contractor.
K**Y
10/10 for quick weight gain
Helped me gain weight in a quick period. Will order more to get to my weight gain goal. Easy to mix, yummy with a banana added 🤗
R**Y
Serious Mass
I’ve only gotten this product yesterday but so far I’m happy with it. Mixes fairly well in a protein blender bottle, chocolate flavor tastes smooth, and almost 700 calories per scoop. I mix it with lactaid milk and water and my body hasn’t had a problem with digesting.
T**R
What They Don't Tell You
What they tell you. It tastes great and is a good supplement to build mass. What they don't tell you. Each serving consist of 2 huge heaping scoops of powder and 24 ounces of fluid (water or milk). This combination results in 48 ounces of liquid delight that they claim is a single serving. On what planet is 48 ounces a single serving? To put this in perspective, that is 2 full to the brim Shaker bottles that are intended to be consumed as one serving. 340 grams of powder from one serving translates into 3/4 of a pound of powder. Again to put this into perspective, the huge tub of powder you will recieve equals ONLY 8 advertised servings. The other thing they don't tell you is the powder is so fine and gummy that the only way to prepare the drink is to use a full sized blender. No Shaker bottles here. Preparing this mix is a mess. The powder is so fine that it creates a gummy mess that adheres to the side of the blender like Venom on Eddie Brock. Prepare to spend a significant amount of time coaxing the paste free to get it to properly mix. Great protein mix, but I sometimes I feel like it would be easier to eat 5 chicken breasts too reach the same calorie goal, than to put down 48 ounces. I realize that it can be broken up throughout the day, but so can multiple meals. There is also the option of using another protein supplement with a realistic serving size, multiple times a day. In the end, I feel like that is all they have done with this product. They have combined a multiple dose, throughout the day protein powder into a single serving, trying to advertise it as a solution that they obviously have not solved.
M**I
Ottimo prodotto
Già acquistato in passato Prodotto conosciuto e di qualità
N**N
Produit parfait pour les ectomorphes !
Comme la plupart ici, j'ai du mal à prendre du poids. Après lecture des avis ici et sur le net, je me décide à tester ce produit ! 52 kilos pour 172 à l'origine, j'ai gagné 3 kilos en 1 mois ! Voir la balance afficher une hausse de poids donne vraiment un sentiment de satisfaction ! Mon alimentation reste toujours la même, à savoir, 3 repas par jour, petit déjeuner, déjeuner et dîner. Je répartis la prise en deux parties, une dose pleine le matin en même temps que le petit déjeuner (ça me donne également de l'énergie pour la journée) et une dose pleine dans l'après-midi ou la soirée après une séance de musculation. Ma séance de musculation ne dure par plus de 30 minutes, je fais de courtes séries mais privilégie des poids lourds. Pas de prises de bide à déclarer, pensez à faire une activité physique pour éviter cela ! Produit à conseiller pour ceux qui ont vraiment du mal à prendre du poids.
A**R
ガリガリの人に見て欲しい
今まで代謝が良すぎて全然太らなくてこれを試してみました。僕の場合1日に1200kcalを2回摂ってるので正直キツイです。味も一気に飲むと甘ったるすぎるので分けて飲むのをおすすめします。ほんとにガリガリで少食でも無いのに178cmの53kgでした。普段の食事等もがんばって1日だいたい3400kcalくらい摂れるようにしていたら3週間で60kgまで増えました。これからもこれを飲んでもっと増やします。僕のように自分を変えたい人にとっては最高の商品だと思います!
M**T
Top Weight Gainer – wirkt und schmeckt 👍
Sehr gutes Produkt! Löst sich gut auf, schmeckt angenehm und hilft beim Zunehmen und Muskelaufbau. Klare Empfehlung für alle, die Masse aufbauen möchten.
M**N
Good
Good quality but result after 20/25 days know
Trustpilot
1 month ago
2 days ago