We Chose The Best Gainer in The UK - 10/2025

The Bulk Protein Company, SERIOUS GAINZ - Whey Protein Powder - Weight Gain, Mass Gainer - 30g Protein Powders (Chocolate, 5kg)

The Bulk Protein Company, SERIOUS GAINZ - Whey Protein Powder - Weight Gain, Mass Gainer - 30g Protein Powders (Chocolate, 5kg)

The Bulk Protein Company

13% OffFree Shipping

Why we love it

Builds muscle with high protein.
Promotes mass gain effectively.
Offers excellent value for money.

Main Highlights

30g PROTEIN PER SERVING TO HELP BUILD MUSCLE - Protein Isolate powder that contains 30 grams of high quality Protein per serving. A convenient and easy way to help you meet your daily protein needs. Use after training to quickly heal micro-tears in muscle tissues, which speeds up recovery, reduces muscle soreness and leads to stronger and bigger muscles over time.
PUT ON SIZE AND GAIN MASS - With 468 lean calories per serving, Serious Gainz protein powder is ideal when BULKING. Use as part of a balanced diet to help add body mass and increase weight gain. Contains 81g of carbohydrates which will help your body absorb the protein within, turning it into muscle mass to help towards improving your overall body composition.
PROTEIN SHAKE THAT TASTES GREAT - Add 3 scoops of powder to 400-500ml of water or milk and mix well to create a great tasting Protein Shake! Can also be enjoyed in smoothies, with oats or when added to a pancake mix. Protein powders don't have to be boring, so we made 10 different flavours for you to choose from.
HIGH QUALITY WHEY PROTEIN - Whey digests quickly and is rich in branched-chain amino acids (BCAAs). One of these BCAAs, Leucine, plays a major role in promoting muscle growth and recovery after resistance and endurance exercise. When amino acids are digested and absorbed into your bloodstream, they become available for muscle protein synthesis, which is the creation of new muscle.
EXCELLENT VALUE 5kg TUB WITH 40 SERVINGS - With up to a month's supply of high quality protein powder, we offer great value for your money compared with other brands. We recommend one serving per day to consistently meet your daily protein goal. Consume immediately post-training on workout days and between breakfast and lunch on non-workout days. Comes with scooper for measurements.

8.7

Excellent

8.7

Excellent

The Bulk Protein Company

The Bulk Protein Company, SERIOUS GAINZ - Whey Protein Powder - Weight Gain, Mass Gainer - 30g Protein Powders (Chocolate, 5kg)

13% OffFree Shipping

Why we love it

Builds muscle with high protein.
Promotes mass gain effectively.
Offers excellent value for money.

Main Highlights

30g PROTEIN PER SERVING TO HELP BUILD MUSCLE - Protein Isolate powder that contains 30 grams of high quality Protein per serving. A convenient and easy way to help you meet your daily protein needs. Use after training to quickly heal micro-tears in muscle tissues, which speeds up recovery, reduces muscle soreness and leads to stronger and bigger muscles over time.
PUT ON SIZE AND GAIN MASS - With 468 lean calories per serving, Serious Gainz protein powder is ideal when BULKING. Use as part of a balanced diet to help add body mass and increase weight gain. Contains 81g of carbohydrates which will help your body absorb the protein within, turning it into muscle mass to help towards improving your overall body composition.
PROTEIN SHAKE THAT TASTES GREAT - Add 3 scoops of powder to 400-500ml of water or milk and mix well to create a great tasting Protein Shake! Can also be enjoyed in smoothies, with oats or when added to a pancake mix. Protein powders don't have to be boring, so we made 10 different flavours for you to choose from.
HIGH QUALITY WHEY PROTEIN - Whey digests quickly and is rich in branched-chain amino acids (BCAAs). One of these BCAAs, Leucine, plays a major role in promoting muscle growth and recovery after resistance and endurance exercise. When amino acids are digested and absorbed into your bloodstream, they become available for muscle protein synthesis, which is the creation of new muscle.
EXCELLENT VALUE 5kg TUB WITH 40 SERVINGS - With up to a month's supply of high quality protein powder, we offer great value for your money compared with other brands. We recommend one serving per day to consistently meet your daily protein goal. Consume immediately post-training on workout days and between breakfast and lunch on non-workout days. Comes with scooper for measurements.

We scanned 263 products

We reviewed these offers relevant to the Gainer 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, USN, Weider, The Bulk Protein Company, all of which have a reputation for consistently delivering high-quality products that users love and innovative approaches for function & design.

For the best Gainer in the market, we considered we took a deep dive into 1316 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.

Best Gainer of 2025

We scanned 263 products

We concluded that: