Posted on 05 May 2014
4 min read
For the last few years my weight gainer of choice has always been Mutant Mass.
It’s my ‘clutch’ supplement, dependable in crucial situations when I need that big hit of muscle and size.
However, I recently found Optimum Nutrition’s Serious Mass on offer online, and being a big fan of their Gold Standard Whey (and a bargain), I decided to broaden my horizons and give it a go.
This is how I got on…
Serious Mass is a hardcore weight gainer which is literally bursting at the seams with calories.
It packs in a gargantuan 1,250 calories per serving (more than any other weight gainer on the market) making it the ideal product for hardgainers looking to add some serious meat to the bone.
This isn’t just a protein shake, this is an utter landslide of calories.
Mixed with whole milk, you’re going to be knocking back over 1,500 calories per shake!
Each serving size also contains a 50g protein blend, 250g carbs, 5g fat, 24 vitamins and minerals, creatine, and glutamine.
The protein formula comprises a mix of whey protein concentrate, egg albumen, alcium caseinate, and sweet dairy whey.
This makes for a moderate-to-slow release of protein throughout the day, meaning your body will be constantly feasting on the good stuff.
The carbs come from malodextrin (would have preferred a superior source here but hey ho), and of this only a relatively small proportion (20g) is derived from sugar.
It’s also good to see some other goodies, such as creatine and glutamine, thrown into the mix, as this really gives Serious Mass a comprehensive nutritional profile for aiding gains.

Using a blender, I had no problems mixing the Serious Mass powder into a smooth shake.
However, using just the shaker bottle was a different story.
Getting the thing into a drinkable state was like training for a charity wankathon, and I could never seem to get rid of those last few clumps of lumpy powder.
Although it’s not too bad, the taste of Serious Mass is also not a strong point.
It’s sweet and rich, but this is par for the course with a high calorie weight gainer, so no real complaints here.
I opted for the chocolate flavour, and, mixed with milk, it’s certainly not as bad as some people complain.
I took Serious Mass twice a day between three regular meals for 4 weeks.
This was alongside a basic 5×5 strength and size routine and some light cardio on rest days.
In just over a month I managed to gain 12 pounds (approx 0.86 stone) in bodyweight.
While most of this was definitely muscle mass, I did, inevitably, gain some fat, but this is to be expected with such a hardcore weight gainer.
Serious Mass also helped me to add considerable weight to my 5RM on bench, which is an exercise I’ve struggled to make gains with over the last few months.
If you’re anything like me, a two-scoop serving of Serious Mass will cause some major bloating.
The scoop that comes with the bag is about the size of a cereal bowl!
I constantly felt full, sometimes uncomfortably so, and was reduced to waddling around the office where I work like a pregnant toad.
As such, towards the end of the month I tended to use just the one scoop, which works out at about 700 calories a serving.
The problem with this is that the protein serving goes down to about 25g, so I topped each serving up a bit with some basic whey.
You’re also going to be subjected to some severe rectal turbulence while taking this supplement, so brace yourself and everyone else within a 10 metre radius of your anus.
And, mark my words, going to the toilet will feel like giving birth to a baby rhinoceros.
You can usually pick up 5.4kg of Serious Mass online at Amazon for around £40 or $50.
This works out at a similar price to Mutant Mass and slightly more than bargain basement brands such as Complete Mass from Bulk Powders.
However, the nutritional profile of Serious Mass, like all other Optimum Nutrition products, is far superior to competing brands, making it excellent value for money in my book.
Are you a hardgainer or ectomorph looking to put on weight and add some serious muscle to your frame?
If so Optimum Nutrition’s Serious Mass is the perfect supplement for you.
It’s overflowing with quality calories, protein, carbs, as well as other muscle building goodies, and provides excellent value for money.
It also works very well as an MRP if you’re the kind of person who struggles to get in a proper meal at every sitting.
Ultimately, if you’re consistent with your diet and training while using Serious Mass, you will almost definitely see significant results.
For the best price on Optimum Nutrition’s Serious Mass shop here at Amazon.
Have you tried Serious Mass?
Thinking of giving it a go?
Got any questions?
I’d love to hear your thoughts in the comments section below!
I’ve just started on Serious Mass.
I currently weigh 50kg.
Am a bit confused with the serving size.
Each scoop is 250ml or 8oz, which amounts to roughly 224g per the label, 2 scoops equal to 334g.
If my Maths is correct 2 heaped scoops is far more than 334g.
Am I looking at this wrong?
Hi Imran, 334g is equal to two HEAPED scoops, which makes the serving size slightly larger than the scoop size.
If I split the 2 scoops per day of Serious Mass into 4 servings will the effect be the same?
And how long will it take to notice weight gain?
How effective is it?
Experiencing acid indigestion and excessive salivation since started taking this in divided doses.
Any suggestions or should I stop taking this?
I have 4 stones in kidney so I take serious mass weight gainer.
Come again?
Thanks man, that’s a great review you have there!
I’m planning to get the 6lb and trying to calculate my servings per month.
Given that I’d probably be having one serving of a one scoop per day, how long do you think the bottle will last for me?
And by doing so, how soon would I be able to see the results if my workouts are some how moderate in intensity as in 3 hours per week?
One more thing if I may, as for a female, would this work as a proper weight gainer?
And how effective would it be if one is not working out sufficiently yet have an active day, be for a male or a female please?
Pardon me for the pile of questions but any help would count big mate.
Hi Mohammed, thanks for your comment.
OK, so bear with me while I calculate this in metric measurements.
6lbs = 2721.55g
A single serving of Serious Mass is 167g, so 2721.55/167 = 16.3
So if you take a single serving a day, it will last you around 16 days.
If you train consistently with heavy compound lifts and consume enough calories/protein, you should definitely begin to see results.
Male or female, this product will help you up your calorie intake for size gains, but if you’re not training hard and eating crap, you WILL get fat.
Hope that helps, let me know if you have any further questions!
Harrison
Hello.
The supplement clearly states that it is for non-vegetarians.
If half a scoop is taken with vegetarian diet, will that be just fine?
Or else what procedure must vegetarians follow while taking ON Serious Mass?
Thank you.
If it states it’s not for vegetarians, it’s not for vegetarians, no matter how much you take.
For more info on vegetarianism and bodybuilding, check out the following article:
http://www.gym-talk.com/vegetarian-bodybuilding-diet/
Nice review.
Serious Mass is one of the most effective mass gainers I have come across.
Within a month I gained almost 8 pounds.
I would also suggest BSN True Mass and Muscletech Masstech as they are effective too for lean mass gain.
Hi Rohan, thanks for your comment, definitely can’t go wrong with BSN!
Hey.
You said when you started using one scoop (700 calories, 25g protein), you topped it with Impact Whey Protein, so that you could consume more protein.
I’d like you to give more details on that.
Because I’m planning to consume 1 scoop of Serious Mass (1 scoop, not 1 serving!) mixed with milk after my workouts.
I workout 4 times a week, so after every workout one scoop.
So should I start using Impact Whey to top it up?
Or please give me other ways to add more protein since I’d only be consuming 25g because of 1 scoop.
Thank you 🙂
Hi.
This was to cut down the total calories I was consuming per shake while still getting a decent hit of protein.
Just start by taking the recommended serving size – I only cut it down because I was having bloating issues.
I am a 20 year old male about 5’11 and I started taking Serious Mass in the summer of 2019.
I weighed about 155 lbs and now today in November of 2020 I weight 215 lbs.
I am extremely ambitious and often will try to surpass expectations, I can say for a fact that Serious Mass is very effective I have never seen results like it in my life.
I took it 3 times a day for multiple months to get where I am currently at, but be careful because if you take it without working out you will gain fat very easily.
Does Serious Mass or other mass gainers contain beef in it?
No
It contains 48 hour marinated chicken inside
Best comment, ever!!
Guys, need some serious help.
I’m a male of 22, my height is about 5’4″, and my weight is 48kg (106lbs).
My bones seems short but I want to add muscles (but not that huge bulky bodybuilder type) to my slim body so that I can look tall & fit.
So for that:
1) What would be better, SERIOUS MASS or WHEY PROTEIN?
2) The actual dosage of SERIOUS MASS is 4-8 scoops per day… what if I take 1-2 scoops per day, then will it increase my weight and muscles?
3) If i take WHEY PROTEIN 1-2 scoop what will it do?
And yes I am working out in a GYM (light weights only).
If you’re going for a lean, shredded look I would avoid mass gainers altogether, as you will put on excess weight.
In your case, I would recommend a simple, low-calorie whey protein shake alongside a full-body weights routine several times per week and some high-intensity cardio (sprints, boxing, spinning, etc).
Check out our articles on training and nutrition for some more help:
http://www.gym-talk.com/training/
http://www.gym-talk.com/nutrition/
http://www.gym-talk.com/reader-q-and-a/
Sir my age is 24 and my weight is 65kg.
I buy Serious Mass 12lbs at Healthcart and I take after exercise two times a day, one is in the morning and the other is in the evening.
Please guide me for my diet and which time I should take Serious Mass.
The timing of your shake is not important – just keep a track of macros on a daily basis to make sure you are hitting your daily quota.
Use the supplement as a snack between meals and/or as a convenient post-workout hit of protein.
The rest of your diet should comprise healthy, wholesome, “real” foods.
Lots of meat, healthy fats, veg – i.e. steaks, fish, olive oil, nuts, greens, etc.
Yeah, I completely agree with you.
It’s worth the money.
I have even bought 5.4 kgs for 40 Pounds and it’s really effective.
Thanks for the share.
I really appreciate your efforts in delivering such an ultimate review.
Cheers Adit 🙂
Dear Harrison,
I need your help to gain weight and muscles by taking Serious Mass Gain.
Someone suggested me Serious Mass Gain.
I want to know if this is effective for me or not according to my weight, height and workout I am doing everyday and food which I take.
My Age is 29, height is 5’7″ and weight is 61 KG.
I started gym 3 weeks ago with light weight.
I use normal food everyday like, breakfast, lunch and dinner with 6 eggs without yolks and bananas.
Please explain me how should I use serious Mass Gain that should give results without any side effects.
I am afraid if I will take this without knowing of exact use with exact calculation it will side effect on me.
Please help me in this so I can use this properly that will give me results.
Thanks
Hi Ahmed – you should take Serious Mass between meals (not as a meal replacement) to beef up your daily protein/calorie intake.
Hi,
I just started my protein diet and I wanted to get some advice.
So I’m actually 52kg for 175cm and I want to gain 6 more kilos in the coming month.
I’ve already bought the Serious Mass 12lbs and I’m taking half of the scoop in the morning and the other half after workout (5 days a week).
Do you think it will work for me or should I take 2 times the whole scoop?
Thank you!
Hi there.
Halving the measure is a good way to start if you’re new to mass gainers, then once your body starts getting used to the added calories, consider upping the serving size.
Sir, I have purchased 2 packets of Serious Mass gainer 12 lbs.
I am using it for 15 days but I haven’t found any result so suggest me Sir.
How should I use it for better results before it gets completed?
My first packet is on the verge of completion but didn’t gibe any results.
Sir plz tell me which diet plan should I follow or how to use Serious Mass gainer?
Or how many scoops should I take in a day???
Firstly 15 days is far too short a time to start seeing results, and, secondly, without knowing you, I’d say that looking for answers in supplements is not going to give you the results you’re after.
Start following a full-body workout routine full of compound lifts (5×5 or Golden Six) and focus on consuming lots of protein from healthy, wholesome sources (steaks, fish, eggs, etc) before you even consider taking any supps.
Hi,
I’m 15 and I weigh 50kg.
I train 4 times a week with full body workouts.
I’m a serious hard gainer and I just want some quick size and muscle.
What should I be taking supplement wise?
If I was to buy this how would I take it?
Thanks
Hi Lennon.
If you’re training as you say you are and have a good base diet in place, then, yes, I would certainly recommend a gainer such as Serious Mass to help provide extra calories.
When taking it, just make sure you’re supplementing BETWEEN meals, and not using it as a meal replacement, otherwise you will not be benefiting from the additional calories.
Feel free to ask my anything else 🙂
Harrison
Hello there, I’m wanting some help, I’m looking to gain muscle mass!
I’m about 12.5 stone right now I’ve bought mass gainer and been taking it but been getting paranoid with getting belly?
Is this normal to get belly when taking this I’m looking to gain weight and muscle mass and then shred in the summer lose as much body fat as possible.
Also got Whey Standard Gold which I’m taking now as I’ve come off mass gainer – been paranoid with my stomach!
If you could give me advice this would be much appreciated.
Hi Jonathan.
Yes, it’s normal to develop a bit of a gut while taking mass gainers of this ilk, as this is not really a ‘clean’ bulk.
Just keep training hard and eating well and the excess body fat will soon come off.
To be honest I’m not really a fan of ‘bulking’ and ‘cutting’ cycles – I would always advise a more sustainable long-term plan instead.
Charlie wrote an article covering this a few years ago, you should have a read:
http://www.gym-talk.com/lean-bulking/
Do let me know if you have any more questions, and good luck with your goals!
Hey I am 17 years old and about 5’10 1/2″ and weigh around 66kg or 145 lbs.
I have been working out for a while – about 6 months – and I just bought Serious Mass to help me with my gains.
I eat a lot of fruits – an apple, a banana, an orange.
I try to get around 3,000 calories in but with Serious Mass it becomes 4,500.
The problem is I took it for the first time today.
I took one scoop just to try it out after eating rice, meatballs, potatoes and tomato sauce.
I felt like I m about to explode when I took Serious Mass haha… and when I went to the bathroom it seems like it all came out… my puss even took a bit the color of the shake.
Is this just because my stomach isn’t used to the amount of calories… because I ate all that and drank Serious Mass in about 30 mins.
How can I make the most out of Serious Mass, make my body absorb the most… should I drink it through a longer period?
Drink more water?
Take some sort of vitamins to help with the digestion of all that?
Hope you answer haha.
Thanks.
Thanks Nour for your very detailed comment – just what I wanted to read over breakfast haha!
In your case I would simply advise lowering the serving size and then gradually increasing it back up to the recommended 2 scoop serving.
That way your body will get used to the calorie increase and it wont be such a shock to the digestive system.
Hi,
Great review, I just had a question.
While taking this as a supplement would you recommend taking whey protein after workouts as well or would replacing postworkout protein with a serving of this suffice?
In that case would it be fine if 1 serving is taken in the morning and 1 after working out?
This will suffice as a post-workout shake – no need to bother with another.
And, yes, 2 servings a day in addition to regular meals would be ideal.
Sir I have bought 12 lbs chocolate Serious Mass.
But it hardly tastes like chocolate and is not that sweet either.
It’s really hard to mix in a shaker with water, few clumps are left at last.
I verified with customer care of ON using my lot number.
They said my product is authentic.
I’m not convinced that it’s original still
Can it be fake due to bad mixability and taste as described above?
Looking forward to your reply 🙂
As I mentioned in the review, the taste and mixability of Serious Mass is certainly not great, so it probably was authentic.
Just get it down your neck and quit complaining – the results more than make up it!
Hello there!
I need important info.
I’m 19 with 6’2″ height and just 60 kg, that typically makes me a hardgainer and ectomorph.
I just started doing 5×5 SL workout a week ago.
Now is it okay for me to take ON Serious Mass?
If yes, then how many scoops should I take per day and at which time will it be best for consuming?
Hi Galib.
Thanks for dropping by.
Yes, Serious Mass is ideal for hardgainers, and will especially complement a good solid routine such as SL 5×5.
I would start by taking one serving twice a day between meals – and one after your workout – and then gradually increasing that to two scoops once your body becomes accustomed to the calorie increase.
Hope that helps.
Harrison
Hello Sir Harrison.
I am 19, height 5’5″, weight 47kg.
I want to gain muscles, about 6 to 8 kgs.
I work out five days a week (including kickboxing).
I have two options:
1. ON Serious Mass
2. ON Gold Standard Whey Protein
I can afford only one pack of above (12lb).
I have a high metabolism rate.
So which one I buy Sir?
(I am vegetarian, can’t add much protein etc from food, eggs in supplements are OK)
If you have a fast metabolism and are a typical hardgainer, I would certainly suggest Serious Mass.
Hi Harrison, I am a 17 year old who is 5 ft 11 and weigh just over 10 stone.
Your review really seemed to make me interested.
Last night I ordered this product online without reading much reviews.
Would this product work in the aspect of trying to gain just over a stone with doing my usual workout to gain muscle also or would I have to gain weight first and then turn it into muscle?
Thanks.
Hi Daniel.
Just use it alongside your workout routine.
If you’re hitting those big compound lifts (squat, deadlift, presses, rows, etc) several times per week, eating a healthy protein rich diet, and supplementing with Serious Mass, then you should definitely see results.
Feel free to get in touch any time you have any more questions 🙂
Harrison
Hey Harrison,
I just ordered Serious Mass and I work out 5 times in a week.
It is hard to gain weight for me so that’s why I ordered Serious Mass.
I need some help with the times I take this?
And what about the days I don’t workout, do I still take the shake or only when I work out?
And is it better if I take it after workouts or it doesn’t matter?
Hope to hear from you.
Maikel
Hi Maikel, thanks for your comment.
Take Serious Mass between meals every day to bolster your daily calorie intake – and it also works well as a convenient hit of protein post-workout.
Hi,
My age is 28, my height is 5.6 feet, my weight is 58 kgs.
I am working out from last 3 months (5 times a week), I need to gain some weight, I look very slim.
I am taking Serious Mass also but can’t see much results.
What should I do to gain mass?
Regards
Navi
Hi Navi.
First off, I would like to reiterate that you should not be looking for answers in supplements, especially if you’re new to lifting weights (3 months is far too short a timeframe to expect decent results).
Building a strong, muscular body takes years not months.
You need to focus on nailing the basics first before worrying about supplements.
Your workouts should be full-body orientated and full of the main compound lifts (squat, deadlift, presses).
Some good places to start are:
http://www.gym-talk.com/reg-park-beginner-routine/
http://www.gym-talk.com/george-eiferman-full-body-workout/
http://www.gym-talk.com/arnold-schwarzeneggers-golden-six-routine/
http://www.gym-talk.com/reg-park-5×5-routine/
http://www.gym-talk.com/stronglifts-5×5/
Also make sure your diet is full of wholesome, healthy food with lots of protein – steaks, fish, poultry, eggs, nuts, greens, etc.
I recommend you check out the following article which has lots of relevant advice:
http://www.gym-talk.com/10-old-school-commandments-for-building-muscle/
Only when the basics are in place should you be using supplements – but please bear in mind they are only a very small piece of the overall puzzle.
Hope that makes sense.
Good luck with your training.
Harrison