We Chose The Best Weight Gain Powder in The UK - 10/2025

Applied Nutrition Critical Mass Professional - Weight Gain Protein Powder, High Calorie Weight Gainer, Lean Mass (2.4kg - 16 Servings) (Chocolate)

Applied Nutrition Critical Mass Professional - Weight Gain Protein Powder, High Calorie Weight Gainer, Lean Mass (2.4kg - 16 Servings) (Chocolate)

Applied Nutrition

22% OffFree Shipping

Why we love it

High-quality lean mass gainz.
New formula with whey isolate.
Tested for athletic assurance.

Main Highlights

THE UK'S MOST TRUSTED MASS GAINER FOR SERIOUS SIZE & STRENGTH – Critical Mass Professional is the ultimate high-calorie weight gainer, engineered for those who want to bulk up, increase muscle mass, and fuel intense workouts. This mass gainer supplement is trusted by hard gainers, bodybuilders, and athletes looking for serious results.
1,000+ CALORIES PER SERVING – PACKED WITH HIGH-QUALITY PROTEIN & CARBS – Delivers a caloric surplus essential for lean muscle gain. Each serving contains a blend of fast-absorbing and slow-digesting proteins, including ISO-XP Whey Isolate, to maximize muscle recovery and growth. Combined with a premium carbohydrate complex, it helps sustain energy levels and support muscle glycogen replenishment.
POWERFUL CREATINE & GLUTAMINE COMPLEX FOR PERFORMANCE & RECOVERY – Enhanced with Creatine Monohydrate, Critical Mass Professional boosts strength, endurance, and muscle power output for high-intensity training. Includes L-Glutamine & Glutamic Acid, key amino acids that aid muscle recovery, reduce fatigue, and support immune function.
OPTIMAL WEIGHT GAIN FORMULA FOR HARD GAINERS & ATHLETES – Whether you struggle to put on weight, need extra calories due to intense training, or want to bulk up, this high-calorie gainer provides the perfect macronutrient balance. Ideal as a post-workout shake, meal replacement, or between-meal supplement for continuous muscle fuel.
EASY MIXING & DELICIOUS FLAVOURS FOR MAXIMUM ENJOYMENT – Designed for convenience, this instantized protein powder mixes effortlessly in water or milk, creating a smooth, creamy texture with no lumps or grittiness. Available in 6 mouth-watering flavours: Chocolate, Banana, Vanilla, Chocolate Mint, Strawberry, and White Chocolate & Raspberry.
TESTED FOR ATHLETES: at Applied Nutrition we carefully select and monitor each product through our quality management system to bring you the highest level of assurance. Critical Mass Professional is no exception and is tested at an ISO 17025 accredited lab.

8.8

Excellent

8.8

Excellent

Applied Nutrition

Applied Nutrition Critical Mass Professional - Weight Gain Protein Powder, High Calorie Weight Gainer, Lean Mass (2.4kg - 16 Servings) (Chocolate)

22% OffFree Shipping

Why we love it

High-quality lean mass gainz.
New formula with whey isolate.
Tested for athletic assurance.

Main Highlights

THE UK'S MOST TRUSTED MASS GAINER FOR SERIOUS SIZE & STRENGTH – Critical Mass Professional is the ultimate high-calorie weight gainer, engineered for those who want to bulk up, increase muscle mass, and fuel intense workouts. This mass gainer supplement is trusted by hard gainers, bodybuilders, and athletes looking for serious results.
1,000+ CALORIES PER SERVING – PACKED WITH HIGH-QUALITY PROTEIN & CARBS – Delivers a caloric surplus essential for lean muscle gain. Each serving contains a blend of fast-absorbing and slow-digesting proteins, including ISO-XP Whey Isolate, to maximize muscle recovery and growth. Combined with a premium carbohydrate complex, it helps sustain energy levels and support muscle glycogen replenishment.
POWERFUL CREATINE & GLUTAMINE COMPLEX FOR PERFORMANCE & RECOVERY – Enhanced with Creatine Monohydrate, Critical Mass Professional boosts strength, endurance, and muscle power output for high-intensity training. Includes L-Glutamine & Glutamic Acid, key amino acids that aid muscle recovery, reduce fatigue, and support immune function.
OPTIMAL WEIGHT GAIN FORMULA FOR HARD GAINERS & ATHLETES – Whether you struggle to put on weight, need extra calories due to intense training, or want to bulk up, this high-calorie gainer provides the perfect macronutrient balance. Ideal as a post-workout shake, meal replacement, or between-meal supplement for continuous muscle fuel.
EASY MIXING & DELICIOUS FLAVOURS FOR MAXIMUM ENJOYMENT – Designed for convenience, this instantized protein powder mixes effortlessly in water or milk, creating a smooth, creamy texture with no lumps or grittiness. Available in 6 mouth-watering flavours: Chocolate, Banana, Vanilla, Chocolate Mint, Strawberry, and White Chocolate & Raspberry.
TESTED FOR ATHLETES: at Applied Nutrition we carefully select and monitor each product through our quality management system to bring you the highest level of assurance. Critical Mass Professional is no exception and is tested at an ISO 17025 accredited lab.

We scanned 928 products

We reviewed these offers relevant to the Weight Gain Powder within online retailers such as Amazon, eBay and other local retailers, ensuring we covered all major brands and models. The products we selected come from trusted brands like Optimum Nutrition, Kinetica, The Bulk Protein Company, Myprotein, USN, Applied Nutrition, Mutant, Reflex, all of which have a reputation for consistently delivering high-quality products that users love and innovative approaches for function & design.

For the best Weight Gain Powder in the market, we considered we took a deep dive into 4641 online reviews , focusing on elements like user satisfaction, performance in real-world conditions, and long-term reliability. Our ranking also evaluates each review’s relevancy, authenticity, up-to-dateness and depth so that the comparison is more sound.

We concluded that:

The clear winner of our analysis is Optimum Nutrition Serious Mass Protein Powder High Calorie Mass Gainer with Vitamins, Creatine and Glutamine, Chocolate Peanut Butter, 16 Servings, 5.45 kg, Packaging May Vary. We love many things about this product by Optimum Nutrition. What sets it apart from the competition is Supports muscle growth and performance, Healthy, low-fat, high-calorie content, Six tasty, varied flavors.

The best value product for most shoppers and where user satisfaction is continuously the highest is Optimum Nutrition Serious Mass Protein Powder High Calorie Mass Gainer with Vitamins, Creatine and Glutamine, Strawberry, 8 Servings, 2.73 kg, Packaging May Vary by Optimum Nutrition based on online reviews by bloggers, experts and online shoppers.

The biggest bargain at the moment for Weight Gain Powder and the best cost-to-value ratio is Applied Nutrition Critical Mass Professional - Weight Gain Protein Powder, High Calorie Weight Gainer, Lean Mass (2.4kg - 16 Servings) (Chocolate)at Applied Nutrition with a 22% discount.

Our list of the best Weight Gain Powder is updated regularly to reflect new releases and changes in product availability, so be sure to check back often for the latest rankings and discounts.

Best Weight Gain Powder of 2025

We scanned 928 products

We concluded that: