---
product_id: 18548319
title: "Optimum Nutrition Serious Mass Protein Powder, Chocolate Peanut Butter 12LB | Weight Gainer Protein Powder, Mass Gainer with Whey Protein, Creatine, Glutamine, BCAAs, Vitamins & Minerals, Easy Mixing"
brand: "optimum nutrition"
price: "¥51882"
currency: JPY
in_stock: true
reviews_count: 9
category: "Optimum Nutrition"
url: https://www.desertcart.jp/products/18548319-optimum-nutrition-serious-mass-protein-powder-chocolate-peanut-butter-12lb
store_origin: JP
region: Japan
---

# 250g carbs per serving 50g blended protein 1200+ kcal/serving Optimum Nutrition Serious Mass Protein Powder, Chocolate Peanut Butter 12LB | Weight Gainer Protein Powder, Mass Gainer with Whey Protein, Creatine, Glutamine, BCAAs, Vitamins & Minerals, Easy Mixing

**Brand:** optimum nutrition
**Price:** ¥51882
**Availability:** ✅ In Stock

## Summary

> 🚀 Bulk up fast, stay strong longer — Serious Mass means serious gains!

## Quick Answers

- **What is this?** Optimum Nutrition Serious Mass Protein Powder, Chocolate Peanut Butter 12LB | Weight Gainer Protein Powder, Mass Gainer with Whey Protein, Creatine, Glutamine, BCAAs, Vitamins & Minerals, Easy Mixing by optimum nutrition
- **How much does it cost?** ¥51882 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/18548319-optimum-nutrition-serious-mass-protein-powder-chocolate-peanut-butter-12lb)

## Best For

- optimum nutrition enthusiasts

## Why This Product

- Trusted optimum nutrition brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Calorie Powerhouse:** Fuel your gains with 1,200+ calories per 2-scoop serving—because size matters.
- • **Immune-Boosting Formula:** Packed with 20+ vitamins & minerals including Vitamin C and Zinc to keep you strong inside and out.
- • **Carb-Loaded Energy Boost:** 250 grams of complex carbs to keep your energy high and your bulk unstoppable.
- • **Customizable Bulk-Up Shake:** Blend with fruits, nuts, or peanut butter for a personalized, calorie-dense powerhouse shake.
- • **Muscle-Building Protein Blend:** 50 grams of premium whey protein to support serious muscle growth and recovery.

## Overview

Optimum Nutrition Serious Mass Chocolate Peanut Butter is a high-calorie weight gainer delivering over 1,200 calories, 50g of blended whey protein, and 250g of carbohydrates per 2-scoop serving. Enhanced with 20+ vitamins and minerals for immune support, it’s designed for busy professionals and fitness enthusiasts aiming for rapid muscle growth and healthy weight gain. Versatile enough to customize with your favorite calorie-dense add-ins, this 12LB tub is your ultimate ally in achieving serious mass and strength.

## 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.

Review: IF YOU DONT CARE ABOUT CHEMICALS BUY THIS - when I was younger I would pound a couple of these protein shakes before school. However now that I’m older I’ve been a lot more conscious of what I put in my body and I would never buy this product because of the long list of chemicals. Look, if you want to put on muscle FAST get it. However, don’t rely on bs products to keep your body up. We Americans tend to see FAST RESULTS and jump on any product. Read the ingredients NOT the calories (in general) Quality: pretty good 👍🏼 Taste: the peanut butter one is my favorite 9/10 The vanilla is HORRIBLE 1/10 The chocolate is decent 6/10 Dissolves/mixability: not the BEST but it get the job done. ! DIGESTION ! : everyone knows the drill. It’s a bit taxing on your stomach if you know what I mean Scoop size: humongous when I first saw the TWO scoops you need for the protein I was like yeaaa definitely splitting this jawn in to two protein shakes. Summary: don’t rely on weight gainers for ever, only if you need to put muscle FAST or have issue with weight and are really skinny. For moms looking to help their kids and make them feel more confident I think this is a great product. However, eat real food. My biggest advice. You can’t shortcut what nature intended. (I put on a great deal of muscle using this and really did help me bulk up)
Review: Best Purchase that Money can Buy - My most recent purchase from desertcart 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!

## 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

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00OV0VYHI |
| Age Range Description | Adult |
| Allergen Information | Milk, Soy |
| Best Sellers Rank | #1,923 in Health & Household ( See Top 100 in Health & Household ) #2 in Sports Nutrition Weight Gainers #242 in Sales & Deals |
| Brand | Optimum Nutrition |
| Brand Name | Optimum Nutrition |
| Customer Reviews | 4.5 out of 5 stars 4,958 Reviews |
| Diet Type | Vegetarian |
| Flavor | Chocolate Peanut Butter |
| Global Trade Identification Number | 00748927052572 |
| Item Dimensions | 11.5 x 5.5 x 16 inches |
| Item Weight | 12 pounds |
| Manufacturer | Glanbia Performance Nutrition |
| Manufacturer Part Number | 1056371 |
| Material Type Free | Caffeine Free |
| Model Name | ON SERIOUS MASS CHOC PB 12LB |
| Model Number | 1056371 |
| Number of Items | 1 |
| Package Type Name | Tub |
| Product Benefits | Immune Support, Muscle Growth, Weight Gain |
| Protein | 50 g |
| Protein Source | Whey |
| Recommended Uses For Product | Calorie Increase, Muscle Growth, Post-Workout, Weight Gain |
| Servings per Container | 16 |
| Supplement Formulation | Multi-Supplement |
| Total Servings Per Container | 16 |
| UPC | 748927052572 |
| Unit Count | 192 Ounce |
| Vitamins And Minerals | 0.9, 3.7, 30, 5, 700 milligrams |

## Product Details

- **Brand:** Optimum Nutrition
- **Flavor:** Chocolate Peanut Butter
- **Item Weight:** 12 pounds
- **Material Type Free:** Caffeine Free
- **Servings per Container:** 16

## Images

![Optimum Nutrition Serious Mass Protein Powder, Chocolate Peanut Butter 12LB | Weight Gainer Protein Powder, Mass Gainer with Whey Protein, Creatine, Glutamine, BCAAs, Vitamins & Minerals, Easy Mixing - Image 1](https://m.media-amazon.com/images/I/511yjH27xML.jpg)

## Available Options

This product comes in different **Size, Flavor** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ IF YOU DONT CARE ABOUT CHEMICALS BUY THIS
*by A***X on January 2, 2025*

when I was younger I would pound a couple of these protein shakes before school. However now that I’m older I’ve been a lot more conscious of what I put in my body and I would never buy this product because of the long list of chemicals. Look, if you want to put on muscle FAST get it. However, don’t rely on bs products to keep your body up. We Americans tend to see FAST RESULTS and jump on any product. Read the ingredients NOT the calories (in general) Quality: pretty good 👍🏼 Taste: the peanut butter one is my favorite 9/10 The vanilla is HORRIBLE 1/10 The chocolate is decent 6/10 Dissolves/mixability: not the BEST but it get the job done. ! DIGESTION ! : everyone knows the drill. It’s a bit taxing on your stomach if you know what I mean Scoop size: humongous when I first saw the TWO scoops you need for the protein I was like yeaaa definitely splitting this jawn in to two protein shakes. Summary: don’t rely on weight gainers for ever, only if you need to put muscle FAST or have issue with weight and are really skinny. For moms looking to help their kids and make them feel more confident I think this is a great product. However, eat real food. My biggest advice. You can’t shortcut what nature intended. (I put on a great deal of muscle using this and really did help me bulk up)

### ⭐⭐⭐⭐⭐ Best Purchase that Money can Buy
*by A***R on September 18, 2016*

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!

### ⭐⭐⭐⭐⭐ Solid starting gainer
*by A***N on November 7, 2016*

Since starting to workout, I needed something more when it came to protein powder because of my skinny build. It has always been tough for me to put on weight let alone muscle, so I thought I would try my hand at taking a mass gainer. This was the very first gainer I have ever used and I did enjoy it. Now for skinny guys like me, let me be clear that you are NOT only supposed to drink this, you also have to make sure you get your solid meals throughout the day. I currently take a gainer twice a day, once in the morning and once after working out. Then I also have my three meals that consist of nutritional things such as vegetables, carbs, and more protein. The thing about many mass gainers is that the scoops are big, just like in this one. Just one scoop look like a mug you would drink tea from. So keep in mind to get 1250 calories, you have to use TWO of those huge scoops, along with milk which makes it thicker. This gainer is pretty thick and will leave your stomach feeling full, and not just full, it will leave you feeling like you drank cookie batter. Here is what I recommend for "hard gainer" males when it comes to working out and diet to gain that muscle effectively. 1. Make sure you find a protein powder or mass gainer that works for you personally, it could be this one, or something like a Clean Gainer that is easier on the stomach. 2. Make sure you also eat your meals throughout the day because there is no substitute for real food. Gainers are supposed to be there as an extra push to reach your total caloric and protein intake for the day. 3. Always keep track how much protein, carbs, and calories you are taking throughout the day. Try to reach your target every single day to help gain muscle and weight. 4. Workout each body part twice a week to make sure you are getting a lot out of your diet and using it to your advantage instead of letting it go to waste. 5. Lastly, add other supplements to your daily routine such as fish oil, vitamin C, and creatine. All of these will help with staying healthy, recovery, and building muscle. I do recommend this gainer as a starter for anyone out there, but there are many other options to choose from so do your research before hand because everyone is different, you just need to find out what works for you.

## Frequently Bought Together

- 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)
- Optimum Nutrition Micronized Creatine Monohydrate Powder, Unflavored, 120 Servings, 600 Grams (Packaging May Vary)

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*Product available on Desertcart Japan*
*Store origin: JP*
*Last updated: 2026-08-24*