Prices and ratings below were checked on Amazon UK on 21 October 2026 and are refreshed regularly. Amazon prices change daily — the live price is always the one on Amazon. As an Amazon Associate we earn from qualifying purchases; it never changes the order of this table.
Mass gainers are protein plus a lot of carbs. Compared on price per kg — most are cheaper per calorie than whey plus oats, but not by much.
Mass Gainers UK — all 19 products
Prices checked on Amazon UK: 21 October 2026. Prices change daily — the live price is shown on Amazon.
#1
Optimum Nutrition Serious Mass Protein Powder
5.45 Kg
£80.00 £14.68/kg price per kg
- Low fat mass gainer with over 1262 CALORIES and 50g of PROTEIN per serving to support muscle growth* plus 3 g…
- No added sugar protein powder formula with 25 vitamins and minerals and less than 5g fat per serving, plus ov…
- Serious Mass protein powder comes in 6 flavours (banana, chocolate peanut butter, chocolate, cookies & cream,…
#2
NAKED Mass
3531g
£64.99 £18.41/kg price per kg
- ONLY THREE INGREDIENTS: Naked Whey, Naked Casein and Maltodextrin (made from gluten free tapioca). Naked Mass…
- MAXIMUM NUTRITION: 48g of Protein, 249g of Carbs, 1,216 Calories, and 7.8g of BCAAs (branched-chain amino aci…
- MULTI-PHASE CLEAN PROTEIN: Keep protein synthesis up by combining fast release grass-fed whey with slow-diges…
#3
Myprotein Impact Whey Gainer
2.5 kg
£44.99 £34.61/kg price per kg
- 31g of protein
- 50g of carbs
- 388 calories per serving
#4
Serious Gainz Bulk Mass Gainer Protein Powder 5kg Weight Gain Shake
5kg
£39.99 £8.00/kg price per kg
- HIGH-CALORIE MASS GAIN FORMULA WITH ~27G PROTEIN PER SERVING – SERIOUS GAINZ by The Bulk Protein Company deli…
- SUPPORTS MUSCLE GROWTH & POST-WORKOUT RECOVERY – Each serving provides a balanced blend of protein and carboh…
- MIXES BEST WITH MILK FOR A SMOOTHER, MORE ENJOYABLE SHAKE – As a bulking protein powder, SERIOUS GAINZ can be…
#5
Dymatize Super Mass Gainer Rich Chocolate 2943g
2943g
£54.39 £18.76/kg price per kg
- OUR MASSIVE COMBINATION of creatine, carbohydrates, BCAAs and proteins provides valuable nutrients to meet th…
- DEVELOPED SPECIALLY FOR BODYBUILDERS, hardgainers and powerlifters and their specific needs, Protein Weight G…
- EVERY SERVING of Super Mass Gainer provides up to 243 g of carbohydrates, 52 g of protein, 11–12 g of BCAAs a…
#6
Bulk Complete Mass Gainer
£32.35 £12.94/kg price per kg
- High Protein for Optimal Muscle Gain: Each 135g serving delivers 43g of high-quality protein along with 65g o…
- High-Calorie Formula to Support Bulking Goals: With 500 kcal per serving, this mass gainer is designed to hel…
- An easy and convenient option for those looking to increase their calorie and protein intake, whether enjoyed…
#7
MUTANT Mass Extreme 2500
5450g
£50.17 £9.21/kg price per kg
- Extreme Calorie Load | Delivers up to 2,540 calories per day when mixed with 1% milk — engineered for hardgai…
- High-Quality Protein Blend | Contains 92 g of protein from fast, medium, and slow-digesting whey sources to s…
- Complex Carb Matrix | Packed with 510 g of carbohydrates per 2 servings from whole food-based sources like wa…
#8
USN Muscle Fuel Anabolic All-In-One Muscle Mass Gainer
2kg
£30.99 £15.50/kg price per kg
- USN Muscle Fuel Anabolic protein drink mix: High protein shake powder with Vitamins, Minerals, Carbohydrates,…
- Premium women's and men's supplements: USN diet supplements offer proven benefits, when taken alongside a bal…
#9
Animal M-Stak
21 Count
£52.01 £2.26/count price per kg
- Animal M-Stak has been developed for bodybuilders and elite strength athletes who have problems with m gainin…
- Animal M-Stak uses 6 different complexes that help your body get the most out of the nutrients you add to it.…
- Take M-Stak for 21 days. Take it on training days 30-45 minutes before training, on resting days between meal…
#10
MaxiNutrition Progain
1.2kg
£41.00 £41.00/kg price per kg
- MASS-GAIN PROTEIN - MaxiNutrition Progain is the perfect protein powder for muscle mass support. ProGain Stra…
- IMPROVED PROTEIN BLEND - ProGain has a high quality blend of whey protein concentrate & calcium caseinate + 5…
- CLEANER SUPPLEMENTATION - ProGain has NO ARTIFICIAL COLOURS, FLAVOURS & THICKENERS. Whilst also being Informe…
#11
USN Hyperbolic All in One Mass (2000g) Chocolate
2000g
£28.21 £14.11/kg price per kg
- GAIN WEIGHT & BUILD SIZE WITH A HIGH CALORIE SHAKE: Struggling to gain weight? USN’s high calorie mass gainer…
- SUPPORT MUSCLE GROWTH & RECOVERY AFTER TRAINING: Packed with 60g of protein per serving to help build and mai…
- INCREASE STRENGTH & TRAINING PERFORMANCE: With added creatine monohydrate to support performance during high …
#12
MUTANT Mass
56g
£30.19 £13.30/kg price per kg
- HARDCORE MASS-BUILDING CALORIES – Delivers an incredible 1,100 nutrient-dense calories per serving to support…
- ADVANCED PROTEIN FORMULA – Includes whey protein isolate, hydrolyzed whey, micellar casein, and milk protein …
- ELITE WHOLE-FOOD CARB SOURCES – Packed with complex carbohydrates from sweet potato, rolled oats, and waxy ma…
#13
Reflex Instant Mass Heavyweight Gainer
5.4kg
£59.96
- The product contains 1538 kJ/363
- Powder for preparing shakes, versatile; taste, color, and texture may vary slightly depending on the variety.
- Suitable for supplementary use as part of a varied diet – without health or function-related claims.
#14
Kinetica Sports OatGain Mass Gainer–Raspberry Yoghurt
2.4Kg
£49.99 £20.83/kg price per kg
- Irresistible Flavour for Maximum Enjoyment: Kinetica Sports OatGain Mass Gainer comes in two mouthwatering fl…
- Smooth & Easy Mixability: Experience hassle-free mixing with Kinetica Sports OatGain Weight Gainer. Whether y…
- High-Calorie Fuel for Muscle & Energy: Each serving of Kinetica Sports OatGain mass gainer provides 630 Kcals…
#15
SCI-MX Total Mass • Mass Gainer Protein Powder • Chocolate Flavour • 2Kg
2Kg
£21.99 £11.00/kg price per kg
- ⚡ FUEL YOUR MUSCLE GROWTH, WORKOUTS & RECOVERY WITH OUR MASS GAINER. A serious game-changer when it comes to…
- 🏋️♂️ BENEFITS: This mass gainer protein contains two high-quality sources of protein: whey protein concentra…
- 🍫 HOW & WHEN TO USE: Add 3 level scoops (125g) to 400ml of cold water.Recommended no more than 2 servings pe…
#16
Protein Works
2kg
£27.10 £13.55/kg price per kg
- WEIGHT GAIN SUPPLEMENT: Vegan Mass Matrix 360 - GOLD (previously known as Vegan Mass Gainer Extreme) is the u…
- COMPLETE AMINO ACID PROFILE: Its complete amino acid profile provides the building blocks necessary for muscl…
- TRI-PROTEIN BLEND: Vegan Mass Matrix 360 - GOLD contains a tri-protein blend, made from the purest and most s…
#17
Applied Nutrition Critical Mass Professional
2.4kg
£29.21 £12.17/kg price per kg
- THE UK'S MOST TRUSTED MASS GAINER FOR SERIOUS SIZE & STRENGTH – Critical Mass Professional is the ultimate hi…
- 1,000+ CALORIES PER SERVING – PACKED WITH HIGH-QUALITY PROTEIN & CARBS – Delivers a caloric surplus essential…
- POWERFUL CREATINE & GLUTAMINE COMPLEX FOR PERFORMANCE & RECOVERY – Enhanced with Creatine Monohydrate, Critic…
#18
Myprotein Impact Whey Gainer
2.5 kg
£37.97 £15.19/kg price per kg
- High-Calorie Mass Gainer – Each power-packed serving delivers 388 calories with 31 g of premium protein and 5…
- Balanced Macronutrient Formula – Expert mix of high-quality whey protein concentrate and blend of complex car…
- Trusted by Experts & Athletes – Designed with guidance from the Performance Advisory Board, blending science …
#19
Applied Nutrition Original Critical Mass
6kg
£39.89 £6.65/kg price per kg
- PERFECT FOR HARD GAINERS: Original Mass weight gain protein powder is perfect for hard gainers who struggle t…
- WAXY MAIZE STARCH: This serious mass protein powder uses Waxy Maize Starch, which is revolutionary because it…
- HIGH IN CALORIES, PROTEIN AND CARBOHYDRATES: This muscle gain protein powder makes a delicious shake that is …
How to use this table
Ratings are the real Amazon UK owner ratings at the time of checking and the price per kg column is the fairest way to compare value across tub sizes. Click any product to see the live price, current offers and the full reviews on Amazon.
Related reviews and guides
- Best Supplement Stack for Muscle Gain UK (2026): Complete Guide
- How Much Protein Do You Actually Need Per Day? (No BS Answer)
Last checked: October 2026.