Serious Mass
Optimum Nutrition

Serious Mass

High Energy Protein Powder Contributing to Muscle Growth
Loaded with 1258 kcal, 250g of Carbs, & 25 Vitamins and Minerals
8.4 out of 10  (1,100 Reviews)
2 Sizes
2.73 Kilograms
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5 Flavors
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Price: £25.24 (£3.16 / Serving)
In Stock
Flavor Rating: 7.5

Product Overview

What is serious mass?

Serious Mass is the ultimate weight gain formula.* With 1,250 calories per serving and 50 grams of protein for muscle recovery, this instantized powder makes a sizable post-workout and between meals shake.* Serious Mass gives you the tools you need to pack on pounds and - when coupled with serious weight training - develop your physique to the fullest.*


  • Adding Calories Has Never Been This Easy or Tasted So Good
  • 1,250 Calories
  • 50 Grams of Blended Protein
  • Over 250 Grams of Carbohydrates with No Added Sugar
  • Enhanced with Creatine, Glutamine, and Glutamic Acid
  • 25 Vitamins and Essential Minerals

How is it different from other gainers?

serious mass - weight gain formula - 50g of protein. pro complex gainer - lean gain formula - 60g of protein.














Ratings & Reviews

Overall Rating
1,100 Ratings
Verified Buyer Rating
398 Ratings
Average Flavor Rating
7 Flavors
Top Rated Flavor
Chocolate Peanut Butter
By clicking the button above, you agree to entering the Reviews section. Products in the Store are not intended to diagnose, treat, cure, or prevent any disease.
Verified Buyer
  • 9 Chocolate
  • 10 Chocolate Peanut Butter
  • 9 Cookies and Cream
  • 4 Vanilla
  • 8 Strawberry

I have been using this product off and on for a couple of years now. I burn through many calories throughout the day and I'm a hard gainer, so the bulk and easy aborsbing calories in this product is great. I just wish it had a little more protein in the carb/protein ratio. Overall, it's a great product for the price.

  • 8 Chocolate

After training for a Half Marrathon I lost over 10 lbs with the mass gainer I put 15 lbs back on in muscle in a week. I would recomend it if you're trying to make some gains.

  • 9 Chocolate

Im gonna be as honest in this review as possible. Im really one of those underweight teens before i started working out. Im 5'6 and i weighed 112 pounds. Then i started working out and used serious mass. Taste wise, i think the chocolate was delicious. At first, i wasnt gaining weight, but then i noticed it's because this product is so thick and hard to drink that it made me eat less. So i decided to take only half a serving a day (1scoop) so that i can eat more. For the First two weeks after taking 1 scoop a day i gained 10 pounds. The next week i gained an aditional 5 pounds. Yes i did gain "mass" in general, but The only i thing i hate about it was that 70% of the mass i gained was fat and only 30% was muscle. Tho it did increase my strength, i think i'd get on's gold standard instead of this thick smoothie like serious mass to gain lean muscles

Verified Buyer
  • 3 Cookies and Cream

Ok so I've been on this product for a while and it's helped me gained at least 10lbs. Ive always gotten chocolate peanut butter, and the chocolate one. I purchased the cookies and cream one... man to me it's a really bad flavor. Doesn't even taste like cookies and cream. I recommend this product just not this flavor! I wonder if I can do an exhange

Verified Buyer
  • 10 Vanilla

Detailed, long, and honest review for potential buyers: This is great for skinny guys looking to gain weight. Using this, as well as eating more food in general I went from 140 - 155 in less than a month of using it daily. It has to be mentioned that a fair bit of that is in fat, not lean muscle, but hey all things considered not bad. The recommended serving size of "two HEAPING scoops" is pretty dumb. One, the scoop is buried like sunken treasure in the bag, making it almost impossible to get out with the risk of wasting powder since this powder in particular is very sticky. Sticks to hands easily, the scoop, etc. Not a con, but makes you wonder why it may be sticky sometimes opposed to their regular gold standard Whey. So, instead of doing that I use my other scoop from the regular GS Whey from ON, with an average of 3 scoops. I'm estimating that's about half of the 1250 potential calories, coming to about 600 - 700 calories per shake, especially when using milk instead of water. Overall, really good for a weight gainer, at times a bit chunky, but if that affects you your a *****. Just chug it.

What's in Optimum Nutrition Serious Mass

6 Lbs. Banana
Supplement Facts
Serving Size2Scoops(334g)
Servings Per Container8
Per 334g
Energy 5273kJ
Protein 53.1g
Total Carbohydrate 251.4g
Of Which Sugars 29.7g
Total Fat 4.4g
Of Which Saturates 1.3g
Of Which Trans Fat 0g
Dietary Fiber 0g
Sodium 605mg
Vitamin A 299.3mcg
Vitamin D 1.9mcg
Vitamin E 3.5mg
Vitamin C 21.9mg
Thiamin (Vitamin B1) 0.5mg
Riboflavin (Vitamin B2) 0.6mg
Niacin (Vitamin B3) 6.7mg
Vitamin B6 0.7mg
Folic Acid 71.3mcg
Vitamin B12 0.5mcg
Biotin 54.8mcg
Pantothenic Acid (Vitamin B5) 2.1mg
Potassium 1,229mg
Chloride 649mg
Calcium 556.2mg
Phosphorus 190.7mg
Magnesium 74.1mg
Iron 4.3mg
Zinc 4.8mg
Copper 0.6mg
Manganese 0.7mg
Selenium 26.8mcg
Chromium 130.4mcg
Iodine 66mcg
Creatine Monohydrate 1g
L-Glutamine 501mg
Glutamine Peptides 501mg
Choline Bitartrate 607.9mg
Inositol 250.5mg
Maltodextrin, Protein Blend (Whey Protein Concentrate*, Calcium Caseinate*, Egg Albumen), Flavorings, Mineral Blend (Di-Potassium Phosphate, Sodium Chloride, Ferric Pryophosphate, Zinc Oxide, Copper Gluconate, Manganese Sulfate, Chromium Chloride Hexahydrate, Potassium Iodide), Whey Powder*, Medium Chain Triglycerides, Creatine Monohydrate, Color (Curcumin), Choline Bitartrate, L-Glutamine, Glutamine Peptides, Acidity Regulator (Malic Acid),, Inositol, Vitamin Blend (Dextrose Monohydrate, Ascorbic Acid, Vitamin E Acetate, Niacinamide, Biotin, Vitamin A Acetate, Calcium-D-Pantothenate, Pyridoxine Hydrochloride, Folic Acid, Cholecalciferol, Thiamin Hydrochloride, Riboflavin, Cobalamin), Sweetener (Sucralose).
* From Milk
Allergen Information:
Contains Milk, Egg, Wheat (Gluten)

Directions For Serious Mass:

Add two heaping scoops of Serious Mass to a blender filled with 24 oz (710 mL) of water. Blend for 45-60 seconds. Then add a few ice cubes and, if desired, other calorie-contributing ingredients and blend for an additional 30-45 seconds.

Tips: Mixing two scoops of Serious Mass with 24 oz (710 mL) of nonfat or low fat milk instead of water will give you a thicker, creamier, higher-calorie shake. New users may find if beneficial to begin with 1/2 of a serving daily for the first week and then gradually increase to 1 or more full servings several times a day.

Serious Mass is a substantial weight-management supplement that can be used to feed serious calorie needs in a variety of different ways.

Between Meals: Drink 1/2-1 serving of Serious Mass between meals to maintain and support muscle growth as well as contributing to a high-calorie diet.

Post-Workout: Begin drinking 1/2-1 serving of Serious Mass 30-45 minutes following exercise to support muscle growth. Before Bed: Drink 1/2-1 serving of Serious Mass about 45-60 minutes before bed to provide nutrients to help maintain muscle throughout the night.

Note: For best results use Serious Mass combined with intense weight training (3-5 times per week) and a sensible whole foods diet. Also, keep in mind that sufficient recovery between workouts impacts your ability to gain lean mass. Allowing at least 48 hours between workouts involving the same body parts is recommended.

Warnings: Do not exceed the recommended daily dose. Keep out of reach of children. Do not take this product if you are pregnant or nursing a baby. Check with a qualified healthcare professional before using this product if you are under 18 years of age or if you have any known or suspected medical condition(s) including diabetes, hypoglycemia, and/or if you are taking any prescription or OTC medication(s). Food supplements should not be used as a substitute for a varied diet. Store in a cool, dry place.

* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
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