Sports Nutritionist’s review of Optimum Nutrition’s Serious Mass

Fuelling performance and achieving enough food intake to adequately recover from training and drive muscle hypertrophy can be difficult at the best of times.

The volume of food to consume as well as achieving adequate, high quality protein sources is no easy feat.

For many, looking towards meal replacements may be a perfect solution. There are few that are able to achieve all the aforementioned targets quite like Optimum Nutrition’s Serious Mass.

This is more than just a “weight gainer“; Serious Mass is an all in one performance, recovery and muscle mass hypertrophy driving meal. We’re going to explore why this product has been dominating the market for well over a decade and who it may be suitable for.

A Look at the Optimum Nutrition Brand

Optimum Nutrition is a cornerstone of the sports nutrition industry; a pioneer of the industry, innovating and providing some of the best quality products on the market for over thirty years.

Part of the Glanbia global nutrition group, Optimum owns state-of-the-art production facilities and is one of the few sports nutrition companies to manufacture in every product category.

Optimum Nutrition’s procurement team carefully select the most premium grade raw materials for their products. A Certificate of Analysis is required for every ingredient, which is then tested and retested for compliance.

Quality assurance performs daily inspections of the current Good Manufacturing Practices (cGMPs) compliant facilities, which are GMP registered. Notably, Optimum are also strenuously tested by other third-party agencies too.

As they are one of the global leading sponsors of many sports, both team and individual, their products have to be of the utmost quality and labels have to be of virtually perfect precision in order to provide to national and international drug-tested athletes.

I was fortunate enough to work in the sports nutrition industry for the best part of a decade and Optimum Nutrition were always my own personal favorite brand; not just for the company ethos and innovative nature of their product line, but the quality of product being produced was (and likely still is) unmatched.

You needn’t look any further than their 100% Gold Standard Whey protein which has been awarded countless times and is the multi-time, “Protein Powder of the Year”, as voted on and determined by

Read Also: Naked Mass Review – a dirty weight gainer?

Serious Mass In-depth Review

Weight Gainer

  • Loaded with 1,250 calories
  • 50g of protein
  • 25 vitamins and minerals
Seriouse Mass weight gainer supplement

Optimum Nutrition describe Serious Mass as “the ULTIMATE weight gainer” and, quite frankly, it’s hard to argue when you really dive into the product itself and how it could be potentially used and incorporated into the life of an athlete who needs that weight gain edge.

Key Ingredients


Maltodextrin is a carbohydrate powder created from corn, rice, potato starch, or wheat. While it is plant sourced, it is highly processed and digests rapidly, leading to a spike in blood sugar and subsequently insulin.

The one critique of Serious Mass is the inclusion of maltodextrin as it may limit the ideal application window of the product; carbohydrates such as these would be best consumed in around an intense workout, and consuming at other times of the day may leave you feeling fatigued following the spike in blood sugar.

This spike is ideal around training as it can either fuel, or more optimally aid the recovery from, performance.

Protein blend (100% Gold standard whey, calcium caseinate, egg whites and sweet whey)

The protein blend included within the product is fantastic; not just in quality but in effectiveness in relation to muscle protein synthesis stimulation (and ultimately how this impacts recovery and hypertrophy).

A blend of “fast” and “slow” digesting proteins may be more optimal for muscle protein synthesis when compared to a singular protein source alone, showing that Optimum Nutrition have done their homework on the matter!

Micronized creatine monohydrate

One of the most researched ergogenic (athletic performance) aids available, creatine is another great inclusion; not just for exercise performance, but also has been implicated in improving recovery, greater retention and development of lean mass, increasing hypertrophy and weight gain.

A multivitamin and mineral support blend

Serious Mass is also fortified with a comprehensive blend of vitamins and minerals (providing over 25 vitamins) that would not only assist in performance, recovery and muscle growth, but also sustaining / improving physical and mental health overall.

L-Glutamine and glutamine peptide blend

L-glutamine is a conditionally essential amino acid; one that has been implicated in recovery but also performance too. L-glutamine may actually help improve performance by stimulating the creation of glycogen (stored carbohydrate), reducing the build up of fatiguing by-products of exercise metabolism and improve recovery by reducing / attenuating muscle damage post-exercise.

Claimed Benefits of the Product

The major claimed benefit of utilizing Serious Mass is “packing on the pounds”, but does it live up to this hype as a mass gainer?

Per recommended serving, Serious Mass provides around 1,250 calories worth of energy. Considering the average recommended daily intake for an adult is between 2,000 and 2,500 calorie range (depending on gender), It’d be pretty difficult to not gain lean mass incorporating this on top of your regular food intake.

With a whopping 250+ grams of carbohydrate as well as 50g of protein per serving, your body can’t help but use this to fuel hypertrophy, performance and recovery. Tens of thousands of users have hailed its benefits and assistance in helping them gain weight and their preferred mass gainer of choice!

We’d actually recommend splitting the serving as it can be a lot to take in, in one go. Consider having one as a pre-gym meal and the other as a post-gym meal; maximally fueling both performance and recovery!

Read Also: Ashwagandha for Tesstosterone – The secret weapon for massive gains

Is it an Effective Weight Gainer?

bodybuilder working out

Weight change is dictated by energy balance; to gain more weight we simply need to be taking in more energy than is required to maintain our weight so as to either fuel growth or for energy to be stored (as either stored carbohydrate or within fat cells).

From an energy intake perspective, Serious Mass is an effective weight gain yes (if being applied in the right context), but what’s important is to focus on the nuance of weight gain; anyone can gain weight, but what we’re most often aiming to achieve is increases in lean body mass, rather than fat mass.

Serious Mass has a range of ingredients which would aid in the promotion of lean body mass development; a diverse protein blend, creatine monohydrate, L-glutamine and a stack of vitamins and minerals to boot.

Additionally, when we look at “where” the bulk of the energy is coming from, we can also assume there will be a more favorable accrual of lean body mass over fat mass. Carbohydrate overfeeding produces progressive increases in carbohydrate oxidation (usage) and total energy expenditure resulting in 75-85% of excess energy being stored.

Alternatively, fat overfeeding has minimal effects on fat oxidation and total energy expenditure, leading to storage of 90-95% of excess energy. Excess dietary fat leads to greater fat accumulation than does excess dietary carbohydrate and so overfeeding on carbohydrate may help prevent fat accumulation while promoting lean body mass gain alongside a higher protein diet.

Read Also: Top 5 Best Mass Weight Gainers (2021 Review)

Why should CrossFitters consider it?

flipping tire

Crossfit is a highly demanding sport; not only is there a significant aerobic component to the exercise, but also a resistance-based element too.

The body and its various systems are being challenged and taxed in a variety of different ways and this may necessitate a more focused approach to recovery and fuelling.

It has been shown that Crossfit exercise burns a significantly greater amount of calories comparative to more traditional activities.

For those Crossfit athletes looking to increase their lean body mass, this will only make the challenge all the more difficult. A product like Serious Mass, even if using a half serving a day, can help attenuate the energy loss while fueling the athlete to perform and recover more effectively.

It is also likely to help them gain the lean body mass they’re seeking without necessarily gaining an excessive amount of fat mass (which would likely only hinder their Crossfit performance).

Related: CrossFit Strength Training Program and Workouts

Taste & Texture

Optimum Nutrition offer Serious Mass in seven flavours; vanilla, banana, strawberry, chocolate, chocolate mint, chocolate peanut butter and cookies and cream.

Despite what you may be accustomed to from other weight gainers (particularly those which utilize maltodextrin) the flavour is not “sickeningly” sweet; rather, it is quite subtle, and allows you to drink it fairly comfortably without irritating your throat (which some do) and can be quite enjoyable!

Personally, I have enjoyed the chocolate peanut butter flavor the most. I found it to be really tasty when mixed with unsweetened coconut / almond milk.

Read Also: Best BCAA Supplements for Men to Aid Muscle Growth & Recovery

Serious Mass

The texture is where it may let some down. It is a humongous serving, there’s no denying that.

First time users will follow the instructions as laid out, but that is a beginner’s “trap”; to try and fit in that amount of powder into your shaker or blender on first attempt is a “no go”.

It’d be like mixing cement and having personally experienced this myself, I would definitely not recommend it.

Instead, I believe dividing it up into two separate servings is a much better approach. Not only will this help with the texture (and trust me, all weight gainers suffer when it comes to texture, this is not an issue unique to Serious Mass), but it’ll also aid in the digestion of the product itself, as consuming that volume of nutrients and fluids in one go will leave you feeling very bloated and lethargic!

Related: Best Creatine Supplements on the market in 2021


Serious Mass is one of the pioneering products within the mass gainer market and a perfect solution for those struggling to get in those extra calories for muscle growth.

A blend of ingredients designed for perfectly fueling the development of lean muscle, muscle recovery, and exercise performance, we’re huge fans of this weight gain giant!

We would definitely recommend splitting the serving size however as even a half serving would be sufficient calories for promoting muscle growth. It also means you can enjoy your muscle gain meal and not have to suffer through an almighty serving of carbs, protein and fat that would turn anyone’s stomach!