4 products

Crucial Mass-123nutrition
Fitness Culture
Crucial Mass 6kg Weight Gainer
£41.99 £7.00 / kg
Method Mass-123nutrition
Method Mass-123nutrition
Out Angled
Method Mass 6kg
£47.99 £8.00 / kg
Mass gainer supplement package with '123 Nutrition' branding  in a white and red pouch on a white background
Mass Gainer-123nutrition
123nutrition
Essentials Mass Gainer 3kg
£62.99 £21.00 / kg
medi-evil nutrition purely mass gainer banana
medi-evil nutrition purely mass gainer chocolate
Medi-Evil Nutrition
Purely Mass Weight Gainer 5.28kg
£35.99 £6.82 / kg
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Weight Gainer

Pack on size, build serious muscle mass, and hit your daily surplus with our Mass Gainer collection at 123nutrition. Specially designed for hardgainers, bodybuilders in a bulking phase, and high-burn endurance athletes, these all-in-one formulas make consuming the calories required for growth effortless. Available in indulgent classics like Milk Chocolate, Vanilla Ice Cream, and Strawberry, they blend smoothly with water or full-fat milk. Formulated with clear allergen information (milk, gluten, and soy) and featuring vegetarian-friendly options.

Enjoy fast UK delivery (free on orders over £50) and simple 14-day hassle-free returns. Need help structuring your bulk? Read our Choosing the best mass gainer for you.

Frequently Asked Questions

Q: What is the difference between Whey Protein and a Mass Gainer?

A: Whey protein delivers concentrated protein with minimal calories (~120 kcal) for lean recovery. Mass gainers combine high-quality protein with complex carbohydrates and fats to deliver substantial calories (500–1200+ kcal) to help you stay in a caloric surplus.

Q: Do I need to drink a full serving size every time?

A: Not necessarily! If a full serving feels too heavy, you can easily split it into two half-servings—taking one in the morning and one post-workout or before bed—to spread out your calorie intake comfortably throughout the day.