Best Mass Gainer UK: Best Options Compared for 2026

Serious Mass is the clearest choice for a very high-calorie shake: its labelled two-scoop serving supplies about 1,250 kcal and 50g protein. Its 336g portion is also a substantial volume to drink. Choose Applied Critical Mass Professional when you want 42g protein in a smaller 150g serving and Informed-Sport batch testing. Warrior is worth comparing on price only when the exact pack is in stock.

A mass gainer is a high-calorie protein blend. The base is usually whey protein concentrate or a whey, casein, and egg blend. Most of the calories come from carbohydrates, whether that is maltodextrin in cheaper products or rolled oats and oat flour in better ones, with a smaller fraction from fats such as medium-chain triglycerides or flaxseed. Some mass gainers add creatine, vitamins, or digestive enzymes, though most of these extras are cheaper to buy separately.

The honest job of a mass gainer is to make it easier to hit a calorie surplus when food alone is not getting you there. Two scoops blended with milk delivers 600 to 1,250 kcal in 90 seconds. That convenience is what you are paying for, not the ingredients themselves.

Serious Mass gives roughly 1,265 kcal and 50g protein in 336g of Cookies & Cream powder. That is about 15g protein per 100g. Applied Critical Mass Professional gives 42g protein in 150g, or 28g per 100g. The first is built around a larger calorie serving; the second delivers more protein for the amount of powder used.

Choose by the gap in your diet. If you already eat enough protein but struggle to add calories, the large Serious Mass serving has a clear job. If you need a denser protein-and-calorie mix or require batch testing, Applied is the better fit when available.

The cheapest bag is not always the cheapest usable serving. Compare a stocked pack at the checkout price you can actually pay, then choose the serving size you will use.

1. 1

   High-calorie convenience: Serious Mass gives about 1,250 kcal in a two-scoop serving, but that serving uses roughly a third of a kilogram of powder.

2. 2

   Protein density and tested sport: Applied Critical Mass Professional gives 42g protein per 150g serving and has Informed-Sport batch testing.

3. 3

   Budget purchase: Check Warrior Mass only when a 5kg pack is in stock and its delivered cost beats the alternatives.

4. 4

   Smaller top-up: Myprotein Impact Weight Gainer lists 380 kcal per 100g Chocolate Smooth serving; whey and oats offer a more adjustable homemade option.

Whey, oats and milk let you adjust calories without committing to the manufacturer's oversized serving. Blend 30g whey with about 100g oats, then add milk or peanut butter to reach the calorie target you need. The trade-off is a thicker shake and more preparation.

A commercial powder makes sense when that preparation is the barrier. Compare the delivered cost of the full portion you will actually drink, not the cost of a token scoop.

1. 1

   Commercial: A measured powder serving is convenient, but Serious Mass calls for 336g and Applied for 150g.

2. 2

   Homemade: Start with 30g whey and 100g oats; adjust milk, peanut butter and total portion to suit your appetite.

1. 1

   Protein density. Serious Mass Cookies & Cream lists 15g protein per 100g; Applied Critical Mass Professional supplies 42g in 150g, equivalent to 28g per 100g.

2. 2

   Carbohydrate load. Serious Mass lists 250g carbohydrate in a 336g serving. That suits a large calorie target but makes the full serving unsuitable as a small snack.

3. 3

   Added creatine. Both manufacturers list 3g per full serving. Count it toward any creatine you already take rather than paying extra for the same dose twice.

4. 4

   Batch testing. Applied says Critical Mass Professional is tested under Informed-Sport. Verify the exact product if banned-substance testing is a buying requirement.

5. 5

   Serving size. Compare the labelled 336g Serious Mass serving with Applied's 150g serving before comparing their calories, protein or price per use.

Use the current checkout price divided by the calories in the exact pack. A 5.45kg Serious Mass pack contains about sixteen 336g servings. At 1,265 kcal each for Cookies & Cream, that is roughly 20,240 labelled kcal per pack; divide the payable pack price by 20.24 to estimate cost per 1,000 kcal.

Do the same for another gainer using its own labelled serving size and flavour. The live table shows current tracked pack and serving prices, while a sold-out manufacturer price is not an available deal.