Mass gainers rankedTop 10 Mass Gainers
For higher-calorie shakes, hard-gainer routines and easier surplus planning. We compare mass-gainer and high-calorie protein options for UK shoppers, focusing on calories, protein, serving size and whether the product genuinely fits a weight-gain routine.
Ranked on routine fit, label clarity and overall value — never by paid placement.
Ranked listThe top 10 at a glance
Use the cards below to compare the products, then open the top-three table if you want the quickest side-by-side view.
Nutrition data standard: Exact protein, calorie, caffeine and supplement amounts are shown only where this audit found a current source match. Figures marked “Check label” need confirming against the live product label. Last source check: 2026-04-29.
1
Start hereCalorie surplus
A big-calorie mass gainer for people who genuinely struggle to eat enough food.
- FormatPowder
- Protein / serving50 g
- Calories / serving>1,250 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: Serious Mass is the classic benchmark: high calories, large servings and a clear bulking purpose.
Watch-out: The serving is substantial, so check how it fits your stomach and daily calorie target.
2
Good valueCalorie surplus
A lower-calorie gainer-style option for shoppers who want extra calories without going straight to a mega serving.
- FormatPowder
- Protein / serving30 g
- Calories / serving468 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: Serious Gainz may suit people who want a more manageable shake alongside meals.
Watch-out: Check whether the calorie level is enough for your goal; it is not as heavy as the biggest gainers.
3
Also compareCalorie surplus
A heavyweight gainer for people who want a serious calorie and protein shake.
- FormatPowder
- Protein / serving60 g
- Calories / serving1,000+ kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: Reflex sits closer to the big-serving end of the category, useful if you want a proper mass-gainer routine.
Watch-out: Large servings can be hard to drink daily, so do not buy purely on headline calories.
4
A muscle-gain powder with a stronger sports-nutrition feel and a fuller formula.
- FormatPowder
- Protein / serving54 g
- Calories / servingCheck label
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: USN is useful if you want protein, carbs and extra formula support in one shake.
Watch-out: Check whether you want a mass gainer or a more complex all-in-one product.
5
A more moderate gainer option for people who want extra calories without an extreme serving size.
- FormatPowder
- Protein / serving32 g
- Calories / serving478 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: SCI-MX may fit shoppers who want a bulking shake but still need it to be manageable day to day.
Watch-out: Compare calories per serving carefully; moderate gainers can require more food around them.
6
A protein-focused powder that is lighter than most true mass gainers in this ranking.
- FormatPowder
- Protein / serving24 g
- Calories / serving114 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: It could help with protein intake, but it is not the obvious choice if your main problem is getting enough calories.
Watch-out: For bulking, check calories first rather than just protein.
7
A reliable whey protein, but it is more of a lean protein powder than a mass-gainer product.
- FormatPowder
- Protein / serving24 g
- Calories / serving<120 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: It may suit people who want to add protein while keeping food as the main calorie source.
Watch-out: If you need easy calories, a dedicated mass gainer will make more sense.
8
A lean isolate-style protein powder rather than a calorie-heavy gainer.
- FormatPowder
- Protein / serving25 g
- Calories / serving<116 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: ISO100 is useful for contrast: high protein, lighter calories and a very different use case from Serious Mass.
Watch-out: Do not choose this expecting weight-gainer calories.
9
A diet-leaning whey product that does not naturally belong at the heavy gainer end.
- FormatPowder
- Protein / serving20 g
- Calories / serving<125 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: It may work for people who want protein support without a big calorie load.
Watch-out: For a surplus, check whether the calories are enough before buying.
10
A premium-style whey option with more protein focus than mass-gainer focus.
- FormatPowder
- Protein / serving30 g
- Calories / serving<142 kcal
Source checked: Verified figures were matched to a current brand page, retailer nutrition table or pack claim on 2026-04-29.
Editor’s take: Platinum Hydro Whey is a useful comparison if you want quality protein, not a high-carb bulking shake.
Watch-out: It is unlikely to solve calorie intake on its own.
Top-three comparisonCompare our top 3
A quick side-by-side view of the first three products in the ranking. Always check the live product page before buying.
| Comparison point | 🥇 Optimum Nutrition Serious Mass | 🥈 The Bulk Protein Co. Serious Gainz | 🥉 Reflex Nutrition Instant Mass Heavyweight |
|---|
| Serving basis | High-calorie ON serving | Check label | Heavyweight serving |
|---|
| Protein / serving | 50 g | 30 g | 60 g |
|---|
| Calories / serving | >1,250 kcal | 468 kcal | 1,000+ kcal |
|---|
| Carbs / serving | 251 g | 81 g | 201 g |
|---|
| Why compare it | Highest-calorie benchmark | Large-tub value option | Very high-calorie serving |
|---|
| Amazon | View on Amazon | View on Amazon | View on Amazon |
|---|
Label check: Comparison figures can vary by flavour, serving size, formula and pack. Use this table as a shortlist, then confirm the current product label or live listing before buying.
FAQsCommon questions
Plain-English answers to the checks that usually matter before buying.
What makes a good mass gainer?
A good mass gainer typically has a high calorie content and a balance of protein and carbohydrates. Check labels for serving size and ingredients.
Will it make me fat?
Mass gainers are calorie‑dense. Consider your overall calorie needs and goals when adding them to your diet.
When should I drink it?
People incorporate mass gainer shakes at different times, such as post‑workout or between meals, based on their routines. Follow the serving suggestions on the label.
Do I need a blender?
Some mixes are very thick — a blender is helpful, but many shake up fine with water or milk.
Next stepPlanning a muscle-gain routine?
A mass gainer can help with calories, but the wider routine still needs protein, training structure and consistent meals.