Optimum Nutrition Serious Mass Review (Usage & Side Effects)

by Joe Costello, CNC | Mass & Weight Gainers

Serious Mass jarSerious Mass by Optimum Nutrition is one of the most popular mass gainers on the market, but people need to understand just how big of a difference there is between Serious Mass and your average mass gainer.

In this Optimum Nutrition Serious Mass review, we will explain what makes it so unique, break down the ingredients, pros cons, and more. Ultimately, this review will be a comprehensive explanation of why we do not recommend Serious Mass.

To learn about some mass gainers that blow this one out of the water, click here: Weight Gainer Comparison.

Optimum Nutrition Serious Mass review 2022: Is Serious Mass any good?

In short, no we don’t see Serious Mass as a true competitor in the mass gainer space. It serves its purpose, but it is not an elite mass gainer. In this Serious Mass protein powder review, we’ll explain how and why we find the nutritional information and supplement facts to be concerning.

Where to buy Serious Mass gainer at the best price

First of all, how much does Serious Mass cost? Let’s take a look at where to buy Serious Mass & get the cheapest deal on prices:



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Are there any Serious Mass coupon codes or promo discount vouchers?

At the time of writing, there are not currently any available Serious Mass coupon codes, which is unfortunate because it is very expensive. With that being said, we don’t recommend Serious Mass to begin with…so even if we had a discount code for you, we honestly still wouldn’t recommend using it.

What does Serious Mass do?

What does Serious Mass do for you? Serious Mass is designed to help you gain weight, and we do believe it’s effective in accomplishing this goal. The problem is that when most people think about mass gainers, their goal is to gain a lot of muscle.

High quality mass gainers can help you gain a lot of muscle, but Serious Mass comes with what we consider to be a pretty severe side effect: fat gain. The formula contains very high counts of carbohydrates, sodium, sugar, fat, and cholesterol, which can all lead to fat gain.

Serious Mass ingredients list

The main ingredients of Serious Mass are:

  • Maltodextrin
  • Whey protein concentrate
  • Calcium caseinate
  • Egg whites
  • Sweet whey
  • Cocoa


Maltodextrin is a carbohydrate complex that is used almost exclusively in mass gainers and weight gainers. It’s essentially pure carbs, and carbs are the key to gaining weight, regardless of whether it’s muscle or fat.

However, the key is the carb to protein ratio. You want it to ideally be 2:1 carbs to protein. Serious Mass contains way too much maltodextrin per serving at 252 grams, creating a carb to protein ratio of 4:1. This is likely going to lead to fat gain as opposed to muscle gain, which is our primary issue with Serious Mass.

Whey protein concentrate

Whey protein concentrate is the most commonly used form of whey protein because it is the cheapest. Most sports nutrition companies choose to use it to save money, which is unfortunate because it is the worst and least pure form of whey protein.

The problem with whey protein concentrate is that it has not undergone the process of cross flow micro filtration like whey protein isolate has. It has also not undergone enzymatic hydrolysis like whey protein hydrolysate has. This means it’s very unpure, hard to digest, and can therefore lead to digestive issues.

Egg whites

This ingredient is pretty self explanatory…it’s just egg whites. They’re used in the context of this formula to help beef up the protein content, which is again just another cheap way for the manufacturer to increase the protein content.

Ideally, instead of blending together whey protein concentrate and egg whites, you would want a mass gainer that utilizes a bend of pure whey protein isolate. This would lead to a much cleaner, purer protein blend, which would therefore lead to better digestion, absorption, and utilization.

Serious Mass usage: How much Serious Mass should you take & when?

According to the directions on the jar, you should simply take one serving of Serious Mass daily. It does not specify when to take it, but I would personally recommend consuming it after exercising. Taking it after exercise would help replenish some of the nutrients that were depleted during your routine.

Serious Mass calories per scoop

Each Serious Mass serving size contains 336 grams of total nutrients, and those nutrients provide a combined 1,250 calories per scoop, which is a lot. As we talked about before, this is a very intense mass gainer in a lot of ways. A calorie count this high can certainly lead to fat gain, which is a problem.

How to use Serious Mass

The Serious Mass instructions are not very in depth. It essentially just says to take one serving per day. You can use it as a meal replacement supplement, or you can use it as a post workout supplement as I mentioned before. There really is no wrong way to use the Serious Mass gainer.

When to take Serious Mass

It’s best to utilize it after a workout in my opinion. During your exercise routine, your muscles are broken down and nutrients are depleted. That’s why I like the idea of taking it after you exercise. It can help replenish the nutrients and build your muscles back up.

Serious Mass pros and cons

Here are the benefits and side effects of Serious Mass.

Serious Mass benefits

The benefits of serious mass may include weight gain, muscle growth, and effective meal replacement. Outside of that, there’s not a whole lot to gain from this supplement. The potential Serious Mass health benefits do not outweigh the potential down sides in my opinion. Let me explain…

Optimum Nutrition Serious Mass side effects

The point we keep emphasizing all throughout this review is that there is one major Serious Mass side effect: fat gain. We understand that people using mass gainers want to gain weight, but it should be muscle that you want to gain, not fat.

Since Serious Mass contains a lot of calories, sugars, fats, cholesterol, carbs, etc, it’s very possible that this can lead to significant fat gain as opposed to muscle gain. You more ideally want to look for a supplement that uses a 2:1 carb to protein ratio and does not contain such high counts of detrimental nutrients.

The other major side effect is that since the protein blend is so unclean (using whey protein concentrate and egg whites), your body is going to have a tough time digesting and absorbing the protein. This could lead to some gastrointestinal side effects including bloating, indigestion, and more.

Other Serious Mass cons

The only other con we really want to touch on a little more is the unclean protein blend. This con should not be overlooked. It’s not just that you’re taking a cheaper, less effective form of whey protein. It’s also that this blend is so unclean that it may actually disrupt your regular gastrointestinal processes.

Serious Mass complaints & praise (from real ON Serious Mass gainer reviews)

First off, I can actually give you my own personal Serious Mass gainer review as someone who has used it before. For me, it simply did not produce the results I was looking for, and it really messed up my stomach to the point where it was interfering with my daily life.

There are also about 46,000 Serious Mass reviews on Amazon, and it received an average rating of 4.5 out of 5 stars across all of those reviews. That’s a pretty impressive mark, but it doesn’t change the fact that the nutritional profile is very concerning in our opinion.

Several of the customer reviews contain similar complaints as mine…issues with indigestion, stomach pains, and other things of that nature.

Is Serious Mass good or bad? Our conclusion

In case you can’t tell by this point in the review, we do not like Serious Mass very much and don’t recommend it. There’s just too much potential down side here with the unclean protein blend, high calorie count, poor carbs to protein ratio, etc. The digestive problems and fat gain it could cause are too big of a risk, which is why we do not recommend it.

Our final Serious Mass rating

Our rating for Serious Mass is a 3.5/5. It provides a lot of nutrients that can be useful for muscle growth and recovery, but at the end of the day, it just doesn’t have what it takes to compete with the top mass gainers. The poor nutritional profile caused it to lose a lot of points.

Serious Mass FAQs

Does Serious Mass work?

This is a loaded question because it does work in the sense that it helps you gain weight. The problem is that it’s just not the right kind of weight. You want to gain muscle, not fat. There are a lot of ingredients in Serious Mass that may lead to fat gain, which is why we’d ultimately answer no it doesn’t work.

Is Serious Mass safe & healthy?

Serious Mass is safe in the sense that it does not contain any dangerous ingredients that raise any red flags. Just because it’s not a very good mass gainer doesn’t mean it’s unsafe. However, we would say that it is not healthy due to the high calorie count, high cholesterol, high sugar, and high fat counts.

How long does Serious Mass take to work?

If you are using Serious Mass over the long term to try to gain weight, it should start working after about 30 days or so assuming you are using it properly. If you are training and eating right, it is likely you will start to gain weight within a few weeks, but it’s different for everybody.

Are Serious Mass weight gainer results better than other options?

No, in our opinion there are several other options that produce better results than Serious Mass. Our top rated mass gainer has a perfect 2:1 carbs to protein ratio, uses strictly whey protein isolate, and has a very clean nutritional profile. That option is likely to produce much better results.

Certified Nutrition Coach at JNC Enterprises Inc. | Website | + posts

I’m not just a supplement analyst. I’m an extremely qualified one! I am a Certified Nutrition Coach (CNC) and actually received my certification directly from the National Academy of Sports Medicine. I am also a Nutrition & Wellness Consultant, certified by the American Fitness Professionals Association (AFPA).

Hi, I’m Joe Costello CNC

I’m not just a supplement analyst. I’m an extremely qualified one! I am a Certified Nutrition Coach (CNC) and actually received my certification directly from the National Academy of Sports Medicine. I am also a Nutrition & Wellness Consultant, certified by the American Fitness Professionals Association (AFPA).