Buy Now
Buy more, save more!

Buy more, save more!

Buy two or more of the same product you will save an extra 2%! Just add the items to your basket

Optimum Nutrition Serious Mass


Now £25.99

Banana In Stock
Chocolate In Stock
Cookies & Cream In Stock
Strawberry In Stock
Vanilla In Stock
Optimum Nutrition Serious Mass


Now £44.99

Banana In Stock
Choc Peanut Butter In Stock
Chocolate In Stock
Chocolate Mint In Stock
Cookies & Cream In Stock
Strawberry In Stock
Vanilla In Stock
Click to zoom
Click image to zoom

Optimum Nutrition Serious Mass

ON’s Serious Mass is the ultimate weight gain formula

ON’s Serious Mass is the ultimate weight gain formula. If you find it difficult to gain weight, Serious Mass can help you develop the physique you've always wanted! Without adequate calories and quality protein, you simply can’t get any bigger, without enough fuel and muscle-building nutrients like protein, you simply won’t grow! Enter Serious Mass...

What Does It Do?
Each delicious shake delivers an incredible 1,250 calories, but no added sugar. This includes 50g of blended protein to support building muscle and 250g of carbs to fuel your workouts. That’s serious calories, serious protein and serious carbs...that’s Serious Mass!
Container Size: 2727g
Serving Size: 2 scoops (334g)
Servings Per Container: 8

Container Size: 5455g
Serving Size: 2 scoops (334g)
Servings Per Container: 16

Amount Per Serving:

Total Calories: 1250
Protein: 50g
Total Carbohydrates: 252g
-Sugars: 20g
-Dietary Fiber: 4g
Fat: 4.5g
-Saturates: 1.5g
Cholesterol: 80mg
Vitamin A: 5000 I.U.
Vitamin C: 60mg
Vitamin D: 200 I.U.
Vitamin E: 30 I.U.
Thiamin: 4.8mg
Riboflavin: 4mg
Niacin: 50mg
Vitamin B6: 5mg
Folic Acid: 400mcg
Vitamin B12: 10mcg
Biotin: 300mcg
Pantothenic Acid: 25mg
Calcium: 590mg
Iron: 8mg
Phosphorus: 430mg
Iodine: 150mcg
Magnesium: 140mg
Zinc: 15mg
Selenium: 70mcg
Copper: 1.6mg
Manganese: 2mg
Chromium: 120mcg
Molybdenum: 75mcg
Sodium: 410mg
Potassium: 1560mg
Choline (as choline bitartrate): 250mg
Inositol: 250mg
PABA: 5mg
Creatine Monohydrate: 1g
L-Glutamine: 500mg
Glutamine Peptides: 500mg


Maltodextrin, Protein Blend (Whey Protein Concentrate, Calcium Caseinate, Egg Albumen, Sweet Dairy Way), Creatine Monohydrate, L-Glutamine, Glutamine Peptides, Choline (as Choline Bitartrate), Inositol, Paba (Para-Aminobenzoic Acid), Artificial Flavor, Vitamin & Mineral Blend (Di-Potassium Phosphate, Magnesium Aspartate, Di-Calcium Phosphate, Calcium Citrate, Ascorbic Acid, Niacinamide, Zinc Citrate, Beta Carotene, d-Calcium Pantothenate, d-alpha Tocopherol Succinate, Selenomethionine, Copper Gluconate, Ferrous Fumarate, Manganese Amino Acid Chelate, Thiamin Mononitrate, Pyridoxine Hydrochloride, Riboflavin, Chromium Picolinate, Folic Acid, Biotin, Molybdenum Amino Acid Chelate, Cholecalciferol, Potassium Iodide, Cyanocobalamin), Medium Chain Tri-glycerides, Acesulfame Potassium

Please Note: Nutritional facts and ingredients may vary slightly between flavours
Add 2 heaped scoops of Serious Mass™ to a blender filled with 710ml (24oz) of water. Blend for 45-60 seconds, then add a few ice cubes and, if desired, calorie-contributing ingredients.

Tips: Mixing 2 scoops of Serious Mass™ with 710ml (24oz) of skimmed or semi-skimmed milk will give you a thicker, creamier, higher-calorie shake. New users may find it beneficial to begin with ½ of a serving daily for the first week, and then gradually increase to 1 or more full servings several times a day.

Serious Mass™ can be used to feed serious calorie needs in a variety of different ways.

Between Meals: Drink ½ - 1 serving of Serious Mass™ between meals to support a high calorie diet.

Post-Workout: Begin drinking ½ - 1 serving of Serious Mass™ 30-45 minutes following exercise.

Before Bed: Drink ½ - 1 serving of Serious Mass™ about 45-60 minutes before bed to provide nutrients to muscles throughout the night.

For best results, use Serious Mass™ combined with intense weight training (3-5 times per week) and a sensible, whole foods diet.
Reviews (30)

"mixes easily in shaker,tastes great.(chocolate)put on 6lbs in 14 days.being a hard gainer that is good."

Posted by malcolm price  (15th February 2016)


"waste of money.My body didnt respond to it and it tasted like a low fat shake. lots of vitamins but no real gains."

Posted by Mannekuin  (5th July 2014)


"on paper a really good gainer, put on 3kg, however having the full 2 scoops makes me feel ill and the taste is pretty grim (vanilla)"

Posted by gary  (17th December 2012)


"Disgusting, smelt like a pet shop and made me feel sick! (Strawberry)"

Posted by Dean Gibson  (14th August 2012)


"yeah you will gain a littlebit of fat using this due the excesss calories so i reckon to instead use an all in one to bulk up rather than is only extremely hardgainers who dont cant eat a lot should use"

Posted by james  (19th May 2012)

Write a Review
Q Hello, how does it sound serious mass in 1st in the morning and nitro tech as post and again serious mass before bed..does it help me to gain muscel or fat aswell..

If you're trying to gain mass (as seems to be the case), you need to add carbs for after training. You'd be better off switching the Nitro-Tech for Anator if you are only using it after training. Or use both but Anator after training and Nitro when you need additional protein throughout the day.

Q Hi guys at tropicana, can you take this product with muscletech anabolic halo? due to creatine content with serious mass, would it be a health risk? Many thanks

After over 20 years of use and study and safety evaluations, it is pretty clear that creatine doesn't have any negative side effects. Perhaps if you have some kind of kidney disease it could be a problem but otherwise, creatine is extremely safe. We recommend adding it to any weight gainer (that doesn't already contain creatine).

Q Hi, I've been reading the Key Benefits section and it just seems to be gaining weight. Does this increase strength also, like MFA?

The more calories you import the more energy expenditure you will have. Heavy weight lifting will contribute massively to increasing strength and this is why extra calories are needed in order to increase strength levels as well as muscle size.

Q how long will this product last me if i take it daily

16 days if you take 1/2 serving twice per day, as we recommend. Number of servings information is included for all products on our website under the "Nutritional Information & Ingredients" tab

Q i am at a brick wall stage with usn muscle fuel mass and wondering if i should move onto this product as i only have 1 kidney i have to be careful with how much creatine i intake but this says it only has 1 gram so i wouldnt think it'd have much effect ? because i have tried ronnie coleman pro antium and i think 5 grams creatine is too much soo advice would be nice ? thank you.

Hello, Thank you for your query. As far as research suggests, so long as the sole kidney is optimally functioning, and there are no additional, underlying health concerns present, it should not be considered harmful to take small, daily doses of creatine. However, is is always advisable that you seek confirmation from a medical practitioner before making any dietary changes. With this in mind, moving on to Serious Mass is unlikely to propose any problems, and will help you to achieve your desired fitness goals.

Q if you want to gain weight do you need have a workout plan or can you simply take this product along with the meals you have already and just gain weight in general? as i would like to gain weight without having to workout.

If you don't train along with taking this product, you will gain...just probably not as much muscle and more fat. This product is perfectly good to use to add quality calories and protein to any diet but just shouldn't be used to "replace" a meal.

Q is that true that ON have changed their supplier and quality of the product is not as good as it used to be?

believe Optimum have been bought by a company called Glanbia (the largest producer of whey proteins in the world) and so I believe the formulations have been changed recently, so whilst the flavours may have changed, I doubt the quality would have been affected.

Q Not really a question but feedback. Excellent product and EXCELLENT customer service at Tropicana... I have already recommended this site to my friends and family! :)

Thank you very much for the feedback as it is greatly appreciated. Feel free to leave any further comments in the REVIEW section on the product you are viewing.

Q When is the chocolate flavor stock coming in....need to order it A.S.A.P

An Optimum delivery is just being counted into stock in the warehouse, so could be available by the end of the day (if it was on the shipment). If not, should be available tomorrow or Monday.

Q Which is the superior product, this, or Mutant Mass?

Serious Mass is a good product but Mutant Mass is BY FAR our best-selling weight gainer and gets excellent reviews from our customers. It also has a very good fibre and healthy fat blend on top of the high quality protein, so I would recommend the Mutant Mass. For best results, if you aren't taking a creatine product at the moment, add 5 grams of creatine monohydrate powder to at least one serving per day (especially the post-workout one) of the Mutant Mass. To get the best results from your weight gainer, read the excellent article at -

Q wich product has the most calories?out off them all?i am on mutant mass nw an just wunderd if ther wuz enything beter eny price

Mutant Mass is our best seller and has an excellent formula, flavour and at a great price. Other excellent products to gain mass quickly are Mass-Tech and Muscle Fuel Anabolic. Nothing has too many more calories than MM.

Q get this bak in stock asap i want it

It's back in I believe!

Q Hey Would like to known your opinon on whether to stick to Mutant Mass or try Serious Mass?

Both are effective weight gainers. If you are having good results with Mutant Mass and like the taste, etc. You should stick with it. It is our best-selling weight gainer and has an excellent formulation and quality and is about the best value per calorie you can find. However, as with all supplements, you may want to experiment with several products to see which is the most suitable for your particular needs.

Q hi, i am trying to gain lean muscle mass without compromisng my 6 pack abs too much....i understand you will gain some bodyfat in order to gain some muscle size however i would like to keep my bodyfat gain to a diet is very good and lean...and i already take protein this the best product out there to help me gain mass with minimum bodyfat or is there a better product out there ???...and does taking this product mean i dont have to take additional protein supplement ???

As you already understand that taking in extra calories will result in muscle growth and a little body-fat gains then yes this product will help you with your goal.

Q Hi, my names moeed, but u can call me moe. My main goal is to gain muscle mass. Im 17 years old n i have a fast metablism n if i take this product and train 4-5 times a week, then would i see chagnes within less than 6 months? And also, can u give me more advice on how to use this product?

This product should be used to bump up calorie count for your day, increased calorie count will lead to increased weight gain. If you supplement this into your bulking regime then you can expect to see some results within 6 months given that your training and your nutrition are spot on too. We'd recommend supplementing with this product two or three times a day between meals, use one serving for immediately after your workout to help with recovery.

Q hi.... i am using Weider mega mass from a moth and i want to change to serious mass is there any side effect if i change to serious mass suddenly or i have to wait for some days....or i can use serious mass directly after mega mass.. please replay me .... thanks ....

You can switch directly from one to the other without any problems.

Q i am 24 and weigh around 75 kg but really wanna grow my muscle size especially bi's and shoulders so is it good for me and which one??

Building muscle is all down to HIGH calorie intake. Serious Mass or any decent weight gainer like Pvl Mutant Mass, Muscletech Mass tech or Gaspari Real Mass will help you pack on some quality muscle mass providing you are following a high calorie based diet and consume the right amounts of carbs, proteins and fats.

Q I am using serious mass for 2 weeks till now and i am taking 1 scoop in the morning after my training session but i dont see any difference so far,can you advice me if extra 1/2 scoop before bed time will be beneficial or will there be any side effects. 2) Can i take the CLA capsule along with serious mass .

If you are looking for size and strength gains then we would recommend taking 2 scoops twice per day and monitor your weight gain. You should be looking to gain on average 1-2 lbs per week of healthy weight. If this does not do the trick we would recommend taking a look at your diet and seeing where you can add in some extra calories. You should be looking to increase your daily intake of calories by around 500-1000 per day. Cla can also be consumed with serious mass or at any other time in the day.

Q i see this product contains multi-vitamin...and i currently take ANIMAL PAK multi-vitamin....if i start taking this product is it okay to discontinue additional multi-vitamin consumption or is the vitamin and minerals in a single serving of this not enough ?

It is safe to combine both products together.

Q Is there any point using this if I only have one scoop? And how much more protein does milk add?

The recommended serving size for Serious Mass is two scoops, which can be mixed with 710ml of water; adding milk will add some simple sugars (in the form of lactose); some protein (approximately 20g) and fat (depending on whether you opt for skimmed, semi-skimmed or whole milk). Milk will bolster the calorific value, so in that sense, you may find it easier to half the serving size and mix it with milk. Supposing you use 355ml, this will provide approximately 10g of additional protein. I you were to halve the serving size, Serious Mass (alone) will still provide 625 calories, 25g protein and 126g carbohydrates; how many servings you have will depend upon your body composition, fitness goals, the quality/consistency of your eating habits and the intensity/regularity of your the exercise you are doing. I hope this information assists with your query.

Q Is this product suitable for vegetarians? (Halal)? As I'm currently taking mutant mass and found out today it isn't

If a product does not state on its nutritional label 'suitable for vegetarians' or carries the 'Halal' certification, then more often than not, it is not suitable for vegetarians or deemed a Halal product. If you require further clarification, I would advise contacting Optimum Nutrition directly using the following email address:; I hope this information is helpful.

Q Is this suitable for veggies?

The L-Glutamine and Amino Acid Chelate could be from an animal source. We would recommend contacting Optimum direct for clarification at -

Q when the 5.4kg comes back?

I realize this was a late response but it is in stock in all flavours now.

Ask a Question