Reflex Instant Mass Heavyweight
by Reflex Nutrition
Calories that count: a high-protein, high-carb formula built for serious muscle and weight gain.
- Up to 50g protein per serving
- Low fat - under 3g per 100g
- High calorie for bulking phases
- For shakes, smoothies, baking and more
Flavour pictures illustrate the taste, not the powder's colour or ingredients.
Best price today
In stock£54.00
£1.00 / 100g
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Transparent protein profile
What's inside
Values per 100g, with the amount in one 250g serving
20g protein
50g per 250g serving
68g carbohydrates
170g per 250g serving
2g fat
4.5g per 250g serving - very lean
373 kcal
933 kcal per 250g serving
View full nutritional information
| Nutrient | Per 100g | Per serving (250g) |
|---|---|---|
| Protein | 20g | 50g |
| Calories | 373.33 kcal | 933 kcal |
| Carbohydrates | 68g | 170g |
| Fat | 1.8g | 4.5g |
Know when to buy
Price history
Lowest price on record, any flavour or size
£0.69/100g (£36.99 for 5.4kg on 24 Sept 2026)
5.4kg · all flavours · price per pack
- Amazon UKlatest £54.00, lowest £36.99, highest £65.25 in the last 90 days
Quick answers
Is this right for you?
Who is it for?
Reflex Nutrition Reflex Instant Mass Heavyweight is designed for hard-gainers and anyone in a dedicated bulking phase who struggles to eat enough calories. Mass gainers combine protein with carbs and calories to support weight gain and muscle growth during intense training blocks.
What can you expect?
A calorie-dense shake designed to help you gain weight. Mass gainers pack protein alongside a significant amount of carbohydrates and calories per serving. Servings tend to be larger than standard protein powders, so expect thicker shakes and bigger scoops. With 20g of protein per 100g (around 50g per 250g serving), Reflex Nutrition Reflex Instant Mass Heavyweight sits in a competitive position for a mass gainer product.
What else do you need to know?
Reflex Nutrition Reflex Instant Mass Heavyweight is a mass gainer protein powder made by Reflex Nutrition. It comes in 2kg, 5.4kg sizes. Every price on WheyWise is read from the retailer’s own page and re-checked daily and sorted by cost per 100g, so you can see both the cheapest option and how current it is. All links to Amazon and retailer sites are affiliate links - this is how WheyWise stays free.
Frequently asked questions
Where is the cheapest place to buy Reflex Nutrition Reflex Instant Mass Heavyweight in the UK?
The best price we have verified today is £1.00 per 100g for the 5.4kg bag, checked 26 Oct 2026. Use the buy button above to go straight to it.
How much protein does Reflex Instant Mass Heavyweight contain per 100g?
Reflex Instant Mass Heavyweight contains 20g of protein per 100g, with 50g per 250g serving. It is a mass gainer product.
Is Reflex Nutrition Reflex Instant Mass Heavyweight currently in stock?
At the last check, 2 out of 3 tracked variants were in stock. Stock status carries the same fetch time as the price shown above, so check the retailer listing before ordering.
Pick your pack
2 sizes · Chocolate · cost per 100g for each
The 5.4kg works out at £1.00 per 100g. The 2kg costs £1.89. Same powder, 1.9x the price per gram.
Where to buy in the UK
Chocolate · 5.4kg · 1 offer for this selection · sorted by cost per 100g
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