Top 10 Mass Gainer Proteins
These are the UK’s most effective mass gainers — ideal for hard gainers or bulking phases. We’ve compared carbs, calories, protein ratios and flavour feedback to rank the best high‑calorie shakes on Amazon.
- ✅ Updated July 2025
- 🏆 Amazon UK Bestsellers
- 🔍 Evidence‑Based Reviews
Jamie’s Tip: Look for gainers with at least 400 calories per serving, and a protein‑to‑carb ratio around 1:2. Bonus points for creatine or digestive enzymes.
See Rankings ↓
1
Low SugarGluten Free
Optimum Nutrition
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Gold Standard 100% Whey
★★★★★
Low Sugar | 24 g Protein | 5.5 g BCAAs | Double Rich Chocolate | 29 Servings
3
Low SugarLow Calorie
PhD
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Diet Whey Lean Protein
★★★★★
20 g Protein | 123 Calories | Low Sugar | L‑Carnitine, Green Tea & CLA | 62 Servings
4
Bestseller
The Bulk Protein Co.
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Serious Gainz
★★★★★
Mega Mass Blend | 5 kg Tub | 40 Servings | Chocolate Flavour
5
High Carb
Optimum Nutrition
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Serious Mass
★★★★★
50 g Protein | 1,260 Calories | 252 g Carbs | Chocolate Flavour | 16 Servings
6
High Carb
The Bulk Protein Co.
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Serious Protein
★★★★★
Banana Flavour | 4 kg Tub | 133 Servings | Balanced Protein & Carb Blend
7
Gluten Free
Optimum Nutrition
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Platinum Hydro Whey
★★★★★
Hydrolysed Whey Isolate | 30 g Protein | 9.5 g BCAAs | 40 Servings | Milk Chocolate Flavour
8
High Carb
Reflex Nutrition
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Instant Mass Heavyweight
★★★★★
60 g Protein | 195 g Carbs | 1,088 kcal | Chocolate Perfection | 2.7 kg Tub
Best Selling Mass Gainer Proteins (Compared Side by Side)
| 🥇 Serious Mass (ON) | 🥈 USN Muscle Fuel | 🥉 SCI‑MX Mass | |
|---|---|---|---|
| Protein (g) | 50g | 55g | 40g |
| Calories | 1250 kcal | 540 kcal | 470 kcal |
| Price/kg | £40/kg | £35/kg | Best Value £32/kg |
| Carbs (g) | 252g | 77g | 60g |
| Servings | 12 | 16 | 18 |
| Protein % | 20% | 30% | 25% |
| Extras | Creatine | BCAAs | Zinc, B6 |
| Prime | Prime | Prime | Prime |
| Rating | 4.5/5 | 4.5/5 | 4.4/5 |
| Overall | Excellent | Excellent | Good |
| Best For | High Calorie | High Protein | Balanced |
| View Product → | View Product → | View Product → |
FAQs
What makes a good mass gainer?
High calorie density (500–1200 kcal), with balanced protein and complex carbs.
Will it make me fat?
Only if you're eating far above your calorie needs. Aim to use gainers to support muscle recovery, not replace food.
When should I drink it?
Post‑workout or between meals works well. Avoid using it as a meal replacement unless needed.
Do I need a blender?
Some mixes are very thick — a blender is helpful, but many shake up fine with water or milk.
Not trying to bulk? Explore lean whey picks for tone and performance.
See Lean Whey Picks →