

🚀 Bulk smarter, not harder with Serious Mass!
Optimum Nutrition Serious Mass is a high-calorie weight gainer delivering over 1,200 calories, 50g of blended protein, and 249g+ carbs per serving. Enhanced with 20+ vitamins and minerals including immune-supporting Vitamin C and Zinc, plus creatine for muscle power. Ideal for fast metabolisms and those struggling to meet calorie needs, it blends smoothly into rich chocolate shakes that fuel serious muscle growth and recovery.





















| ASIN | B0015R36SK |
| Best Sellers Rank | #4,461 in Health & Household ( See Top 100 in Health & Household ) #2 in Sports Nutrition Weight Gainers #586 in Sales & Deals |
| Customer Reviews | 4.5 4.5 out of 5 stars (29,951) |
| Date First Available | May 7, 2005 |
| Department | unisex-adult |
| Is Discontinued By Manufacturer | Yes |
| Item model number | 1101537 |
| Manufacturer | Glanbia Performance Nutrition |
| Product Dimensions | 8.06 x 8.06 x 10.39 inches; 6 Pounds |
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.
A**N
Solid weight gainer – works great and tastes good!
I’ve been using Serious Mass for a few weeks now, and it's been super helpful for adding extra calories to my day. I’ve always had a hard time gaining weight, and this makes it way easier to get in the calories and protein I need without feeling like I’m constantly eating. The chocolate flavor is actually really good—especially when you blend it with milk, peanut butter, or a banana. Just a heads-up, the serving size is huge (like, 2 giant scoops), so a blender is a must. Don’t even try mixing it with a shaker bottle. I also like that it includes creatine and some vitamins, which saves me from buying those separately. Only downside is it can feel a little heavy if you’re not used to big shakes, so I started with half a serving and worked my way up. But overall, it’s been awesome for helping me bulk up. I’m already seeing some gains.
A**R
Buy it if you want to hit your goal!
I lost 25lbs due to HRT and I have been struggling to gain weight for the past 2 months. No matter how much I ate my body was metabolizing it too quickly. I purchased this product. I only use one scoop, add half whole milk and half water, blend and drink it quickly! BOOM! 💥 Gained 9lbs my first week! I’m finally back up to 122lbs. Only a few more pounds to go. I started HRT about 2 years ago and it was until recently that my body just couldn’t keep weight on. I am currently lifting weights and eating more. This shake really helped me on my journey. I feel like I’m truly making progress. BUY IT! Don’t hesitate if you have a goal in mind! I’m so grateful that I did. Strawberry flavor is delicious 😋
J**T
Almost perfect.
I review everything I buy. Especially what I'm putting into my body. Optimum Nutrition is a reputable company who really knows how to make a great product. I'm a hardgainer like most people who will be using this product. I use a few more supplements from Optimum Nutrition and this is by far my favorite. Besides Serious Mass, I also have Optimums Gold Standard Whey (Chocolate flavor) and Creatine. Let me start off by saying that the Whey's flavor is horrible. I don't understand why everyone raves about how good it tastes. Its distgusting. Serious Mass however does not dissapoint. If you feel the same way about the taste of other Optimum Nutrition supplements don't worry, Serious Mass tastes awesome, mixes very well in a shaker bottle, and contains exactly what im looking for in a weight gainer shake. PRO'S + Tastes great + Loaded with calories + Contains 3 different types of Protein. (Whey, Casein, and Egg Protein) + Very affordable + Easy on the stomach (Depending on the person this may be a problem if you follow the serving size. I'll get into that below) Con's - You may think getting a 12lb bag will last a long time. You couldn't be more wrong. Serving size is 2 scoops per shake. ONE SCOOP IS EQUAL TO 1 CUP OF POWDER. THAT IS ABSOLUTELY MASSIVE. Following the directions would cause to you finish a 12lb bag in 3 days. This is ridiculous. Half the serving and add your own ingredients. - Somewhat high sugar. This product does not add any sugar* However that doesnt mean it doesnt have enough already. its not very high. But its similar to a soda. ***Just to clarify for those that may not know this already. This shake is very filling. I expected this and it could be a good thing for some people but for someone who plans on taking this in conjunction with a meal, they may find it hard and feel very bloated after. Its recommended you eat normally and drink the shakes in between meals. I will be buying this product again and I would recommend it to those who want to try a great tasting weight gainer. You may need to experiment with your own add in ingredients like peanut butter or flaxseed oil to add more calories to makeup for the massive scoop size if you decide to half the serving size. All in all its a great product. I only wish they would have clarified how massive the serving size is a little more.
M**N
Mass Gainer- Michael’s Review
I’ve been using Optimum Nutrition’s Serious Mass Gainer for a few weeks now, and it’s been a great addition to my muscle-building routine. The price is very affordable for the amount of calories and protein you get, making it a solid value. The shipment arrived on time, and the product was in perfect condition. Each serving provides 1,250 calories (with milk) and 50 grams of protein, which has really helped me achieve a calorie surplus and gain muscle. The flavor is fantastic, especially the chocolate, and the texture is incredibly smooth—no clumps or graininess. It’s easy to mix, and I love that it feels like a hearty, satisfying meal replacement. While it can be a bit sweet for some, it’s not a dealbreaker for me. Overall, if you’re looking for an effective, affordable, and tasty mass gainer, Serious Mass is definitely worth trying.
T**S
Good product
It's good so far
ア**M
増量にはこれ。 同じブランドの他のプロテインも使用していましたが筋肉を大きく作るにはやはりこの高カロリーバージョンですね 混ざりづらいのでミキサーを使うといいですね。
M**H
I usually buy a chocolate flavor, so it’s the first time to taste a strawberry, And it was delicious
E**N
I bought this to gain weight. The gin master told me to drink this. It tastes like chocolate. It's good. I plan to buy more when I lose weight.😋👍👍👍👍
B**I
good
S**O
Puedo decir que sí funciona para lo que promete: ganar masa y peso rápidamente. Cada batido tiene muchísimas calorías (más de 1 200 si usas los dos cacitos completos), así que es ideal para quienes les cuesta subir de peso o tienen un metabolismo muy rápido como en mi caso, Se nota el aumento de energía y masa corporal en pocas semanas si lo combinas con entrenamiento. El sabor está bastante bien, aunque es algo dulce. Puede causar pesadez, gases o molestias digestivas si no estás acostumbrado o si lo tomas muy rápido. En fin, lo recomiendo si estás enfocado en ganar peso de forma rápida y no te importa tanto la limpieza de los ingredientes. En mi caso ha sido una buena ayuda para subir de peso de forma controlada. 👍
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