Mass Gainer

Mass gainers (weight gainers) combine protein, carbohydrates and calories for athletes who struggle to eat enough to support muscle size. GymStack stocks leaner gainers and higher-calorie bulk formulas across 260+ products.

Use a gainer between meals, after training, or as a calorie-dense shake when whole-food volume is hard to hit. Compare calories per serving, protein content and flavour so you can match an off-season bulk or a cleaner surplus.

How to choose: higher-calorie tubs suit classic hard gainers; lighter “lean mass” styles suit athletes who already eat well but need an easier surplus. Pair with whey isolate on lower-calorie days, creatine for strength phases, and everyday whey protein when you do not need the extra carbs.

Shop curated brands with fast UK delivery — free over £75.

17% off

Applied Nutrition
Applied Nutrition Critical Mass Original 6kg Strawberry

Sale price £48.99 Regular price £58.99

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17% off

Applied Nutrition
Applied Nutrition Critical Mass Original 6kg White Choco Bueno

Sale price £48.99 Regular price £58.99

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17% off

Optimum Nutrition
Optimum Nutrition Serious Mass 5.45kg Chocolate Peanut Butter

Sale price £73.99 Regular price £88.99
Unit price£13.58 /kg

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17% off

USN
USN Wholefood Gainer 2kg Chocolate

Sale price £33.99 Regular price £40.99
Unit price£17.00 /kg

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17% off

Applied Nutrition
Applied Nutrition Critical Mass Original 6kg Vanilla

Sale price £48.99 Regular price £58.99
Unit price£8.17 /kg

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18% off

MaxiNutrition
MaxiNutrition Progain 1.2kg Strawberry

Sale price £41.99 Regular price £50.99
Unit price£34.99 /kg

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17% off

USN
USN Wholefood Gainer 2kg Vanilla

Sale price £33.99 Regular price £40.99

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Bulk
Bulk Complete Mass 2.5kg Vanilla

Sale price £31.99 Regular price £38.99

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17% off

Applied Nutrition
Applied Nutrition Critical Mass Original 6kg Banana

Sale price £48.99 Regular price £58.99
Unit price£8.17 /kg

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17% off

Optimum Nutrition
Optimum Nutrition Serious Mass 2.73kg Chocolate Peanut Butter

Sale price £43.99 Regular price £52.99

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18% off

NutriSport
NutriSport H3avyweight Mass Drive Anabolic 1.5kg Vanilla

Sale price £22.99 Regular price £27.99

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18% off

Conteh Sports
Conteh Sports Essential Gains 465g Berry

Sale price £32.99 Regular price £39.99

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17% off

DY Nutrition
DY Nutrition Metabolic Mass 6kg Almonds

Sale price £66.99 Regular price £80.99

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Weider
Mega Mass 4000 - Vanilla - 3000g

Sale price £62.99 Regular price £75.99
Unit price£21.00 /kg

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17% off

Reflex Nutrition
Instant Mass Heavyweight - Strawberries & Cream - 2000g

Sale price £37.99 Regular price £45.99
Unit price£19.00 /kg

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17% off

Olimp Nutrition
Gain Bolic 6000 - Strawberry - 3500g

Sale price £66.99 Regular price £80.99
Unit price£19.14 /kg

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17% off

Dorian Yates
Metabolic Mass Gainer - Almond - 6000g

Sale price £91.99 Regular price £110.99
Unit price£15.33 /kg

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18% off

Applied Nutrition
Critical Mass - Original - Strawberry - 6000g

Sale price £65.99 Regular price £79.99
Unit price£11.00 /kg

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17% off

Allnutrition
Mass Acceleration - Vanilla - 3000g

Sale price £39.99 Regular price £47.99
Unit price£13.33 /kg

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17% off

Optimum Nutrition
Optimum Nutrition Serious Mass 5.45kg Cookies & Cream

Sale price £73.99 Regular price £88.99

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18% off

Bulk
Bulk Complete Mass 2.5kg Chocolate

Sale price £31.99 Regular price £38.99

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17% off

Applied Nutrition
Applied Nutrition Critical Mass Professional 6kg Vanilla

Sale price £74.99 Regular price £89.99
Unit price£12.50 /kg

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17% off

Trec Nutrition
Solid Mass - Creamy Strawberry - 3000g

Sale price £44.99 Regular price £53.99
Unit price£15.00 /kg

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25% off

Applied Nutrition
Critical Mass - Professional - White Chocolate Raspberry - 2400g

Sale price £43.49 Regular price £57.99
Unit price£18.12 /kg

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18% off

Applied Nutrition
Critical Mass - Original - Vanilla - 6000g

Sale price £65.99 Regular price £79.99
Unit price£11.00 /kg

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17% off

Applied Nutrition
Critical Mass - Original - Chocolate - 6000g

Sale price £56.99 Regular price £68.99
Unit price£9.50 /kg

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20% off

Trec Nutrition
Solid Mass - Vanilla - 1000g

Sale price £15.99 Regular price £19.99
Unit price£15.99 /kg

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17% off

Trec Nutrition
Mass XXL - Vanilla - 1000g

Sale price £23.99 Regular price £28.99
Unit price£23.99 /kg

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17% off

SciTec
Jumbo Hardcore - Chocolate - 5355g

Sale price £157.99 Regular price £189.99
Unit price£29.50 /kg

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17% off

Reflex Nutrition
Instant Mass Heavyweight - Vanilla Ice Cream - 5400g

Sale price £90.99 Regular price £109.99
Unit price£16.85 /kg

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17% off

Reflex Nutrition
Instant Mass Heavyweight - Vanilla Ice Cream - 2000g

Sale price £37.99 Regular price £45.99
Unit price£19.00 /kg

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17% off

Reflex Nutrition
Instant Mass Heavyweight - Strawberries & Cream - 5400g

Sale price £90.99 Regular price £109.99
Unit price£16.85 /kg

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17% off

Reflex Nutrition
Instant Mass Heavyweight - Salted Caramel - 2000g

Sale price £37.99 Regular price £45.99
Unit price£19.00 /kg

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17% off

Reflex Nutrition
Instant Mass Heavyweight - Chocolate Perfection - 5400g

Sale price £78.99 Regular price £94.99
Unit price£14.63 /kg

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17% off

Optimum Nutrition
Optimum Nutrition Serious Mass 2.73kg Vanilla

Sale price £43.99 Regular price £52.99

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17% off

Weider
Mega Mass 4000 - Chocolate - 3000g

Sale price £62.99 Regular price £75.99
Unit price£21.00 /kg

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17% off

Weider
Mega Mass 4000 - Strawberry - 3000g

Sale price £71.99 Regular price £86.99
Unit price£24.00 /kg

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17% off

Trec Nutrition
Solid Mass - Creamy Strawberry - 5800g

Sale price £79.99 Regular price £95.99
Unit price£13.79 /kg

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19% off

Trec Nutrition
Mass XXL - Chocolate - 1000g

Sale price £20.99 Regular price £25.99
Unit price£20.99 /kg

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17% off

SciTec
Jumbo - Strawberry - 6600g

Sale price £120.99 Regular price £145.99
Unit price£18.33 /kg

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17% off

Mutant
Mutant Mass - Strawberry Banana - 2270g

Sale price £33.99 Regular price £40.99
Unit price£14.97 /kg

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17% off

Mutant
Mutant Mass - Strawberry Banana - 6800g

Sale price £107.99 Regular price £129.99
Unit price£15.88 /kg

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17% off

Mutant
Mutant Mass - Triple Chocolate - 2270g

Sale price £38.99 Regular price £46.99
Unit price£17.18 /kg

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17% off

Mutant
Mutant Mass - Cookies & Cream - 6800g

Sale price £93.99 Regular price £112.99
Unit price£13.82 /kg

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17% off

Mutant
Mutant Mass Extreme 2500 - Triple Chocolate - 9070g

Sale price £118.99 Regular price £142.99
Unit price£13.12 /kg

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17% off

Mutant
Mutant Mass Extreme 2500 - Vanilla Ice Cream - 9070g

Sale price £103.99 Regular price £124.99
Unit price£11.47 /kg

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17% off

Mutant
Mutant Mass Extreme 2500 - Cookies & Cream - 5450g

Sale price £67.99 Regular price £81.99
Unit price£12.48 /kg

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17% off

Mutant
Mutant Mass - Chocolate Fudge Brownie - 2270g

Sale price £38.99 Regular price £46.99
Unit price£17.18 /kg

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18% off

Mutant
Mutant Mass Extreme 2500 - Cookies & Cream - 2720g

Sale price £36.99 Regular price £44.99
Unit price£13.60 /kg

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17% off

Mutant
Mutant Mass Extreme 2500 - Cookies & Cream - 9070g

Sale price £118.99 Regular price £142.99
Unit price£13.12 /kg

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