Skip to content

Next Day Delivery on orders made before 3pm (Mon-Fri)

10% off your first order with code WELCOME10

FREE Next Day Delivery on orders over £100

Muscle Gain

Collection: Muscle Gain

Build size, strength and lean muscle with our premium muscle gain supplements at The Box Supplements. Whether you're looking for high-quality whey protein, mass gainers, creatine or intra-workout support, we stock trusted brands to help maximise muscle growth and recovery. Ideal for beginners and advanced lifters alike, our muscle-building range is designed to support progressive overload, improved recovery and consistent results. Shop muscle gain supplements in the UK with fast delivery and outstanding customer service.

Compare (0/5)

1631 products

Trek Protein Flapjack 16x50g Biscoff

Trek Protein Flapjack 16x50g Biscoff

Regular price £21.99
Sale price £21.99 Regular price
Trek Protein Flapjack 16x50g White Choc & Raspberry

Trek Protein Flapjack 16x50g White Choc & Raspberry

Regular price £21.99
Sale price £21.99 Regular price
Applied Nutrition Critical Whey 2kg - White Choco Hazelnut

Applied Nutrition Critical Whey 2kg - White Choco Hazelnut

Regular price £47.99
Sale price £47.99 Regular price
EHP Labs OxyShred Gummies 400g Juicy Strawberry

EHP Labs OxyShred Gummies 400g Juicy Strawberry

Regular price £20.99
Sale price £20.99 Regular price
Trained By JP Performance Isolate 2kg Caramel Fudge

Trained By JP Performance Isolate 2kg Caramel Fudge

Regular price £48.99
Sale price £48.99 Regular price
MyProtein Impact Isolate Whey Protein 1kg - Vanilla

MyProtein Impact Isolate Whey Protein 1kg - Vanilla

Regular price £28.99
Sale price £28.99 Regular price
QNT Carbo Load 12x700ml - Superfruit

QNT Carbo Load 12x700ml - Superfruit

Regular price £15.99
Sale price £15.99 Regular price
Atlas Superweight Gainer 1500 5kg - Strawberry

Atlas Superweight Gainer 1500 5kg - Strawberry

Regular price £38.99
Sale price £38.99 Regular price
Vilgain Grass-fed Whey Protein 1000g Vanilla

Vilgain Grass-fed Whey Protein 1000g Vanilla

Regular price £25.99
Sale price £25.99 Regular price
Trek Protein Flapjack 16x50g Salted Caramel

Trek Protein Flapjack 16x50g Salted Caramel

Regular price £21.99
Sale price £21.99 Regular price
Nutramino Protein XL Shake 12x475ml - Vanilla

Nutramino Protein XL Shake 12x475ml - Vanilla

Regular price £35.99
Sale price £35.99 Regular price
NutriSport Whey Protein Isolate 5kg - Banana

NutriSport Whey Protein Isolate 5kg - Banana

Regular price £62.99
Sale price £62.99 Regular price
USN Hyperbolic Mass 6kg - Strawberry

USN Hyperbolic Mass 6kg - Strawberry

Regular price £49.99
Sale price £49.99 Regular price
Atlas Superweight Gainer 1500 5kg - Vanilla

Atlas Superweight Gainer 1500 5kg - Vanilla

Regular price £38.99
Sale price £38.99 Regular price
Applied Nutrition Critical Mass Original 6kg - White Choco Bueno

Applied Nutrition Critical Mass Original 6kg - White Choco Bueno

Regular price £40.99
Sale price £40.99 Regular price
Cellucor C4 Whey Protein 46 Servings - Reeces Peanut Butter Cup

Cellucor C4 Whey Protein 46 Servings - Reeces Peanut Butter Cup

Regular price £53.99
Sale price £53.99 Regular price
Applied Nutrition Complete Protein 450g Vanilla

Applied Nutrition Complete Protein 450g Vanilla

Regular price £16.99
Sale price £16.99 Regular price
NutriSport 90+ Protein 5kg - Vanilla

NutriSport 90+ Protein 5kg - Vanilla

Regular price £56.99
Sale price £56.99 Regular price
Nutramino Protein XL Shake 12x475ml - Strawberry

Nutramino Protein XL Shake 12x475ml - Strawberry

Regular price £35.99
Sale price £35.99 Regular price
USN Hyperbolic Mass 2kg - Dutch Chocolate

USN Hyperbolic Mass 2kg - Dutch Chocolate

Regular price £27.99
Sale price £27.99 Regular price

FAQ's

How long will delivery take?

We ship via DPD Next Working Day for orders placed before 3pm. Please allow 1 working day for order handling and dispatch, plus 1 working day transit.

How long do I have to return an item?

You have 30 days from the date you receive your order to return any items.

What happens if I order after the 3pm cut-off?

Orders placed after 3pm will enter our handling queue the next working day, and you’ll then need 1 working day for processing plus the usual 1 working day for DPD delivery.

How do I start a return?

Simply fill out the Customer Returns Form and we’ll send you the return instructions.