CHEAPEST
Size
5kg
19.1g
91
0.5g
0.3g
Whey isolate
Whey Isolate UK
Compare whey isolates by cost per 25g protein.
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19.8g
91
1.3g
0.5g
20.5g
89
1g
0.5g
Size
2kg
21.7g
97
0.6g
0.8g
Size
2kg
22.5g
100
0.8g
0.7g
Size
2kg
20g
91
0.8g
0.7g
Size
2.27kg
21.5g
93
0.6g
0.5g
HIGHEST PROTEIN %
Size
1.8kg
23g
99
0.7g
0.6g
Choose range
20.8g
96
1.3g
0.9g
Choose size
21.8g
90
0.5g
0.3g
Choose size
22g
23
0.1g
0.1g
Choose size
21.3g
91
0.4g
0.3g
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20.5g
93
1.9g
0.3g
Choose size
22g
23
0.1g
0.1g
Size
908g
20.8g
94
1.2g
0.6g
Choose size
20.8g
91
1.4g
0.2g
Choose size
20.8g
94
1.2g
0.6g
Size
900g
22.5g
92
0.3g
0.3g
Choose size
20.3g
90
0.5g
0.1g
Size
1.6kg
18.8g
88
0.7g
0.3g
Size
1.13398kg
22.1g
96
1.5g
0.4g
Size
908g
21.7g
92
0.5g
0.3g
Size
1kg
21.8g
90
0.5g
0.3g
CHEAPEST
Size
1kg
21.8g
90
0.5g
0.3g
Browse All Whey Isolate Products (40)
About Whey Isolate Protein
Whey isolate goes through additional filtering to remove most of the fat and lactose, resulting in a high quality protein source that is typically 90% or more protein by weight. It delivers a complete amino acids profile - including all essential amino acids needed for muscle repair and recovery - making it the go-to choice for people on a strict calorie budget, those with mild lactose sensitivity, or anyone who wants maximum protein per scoop.
We track whey isolate products across UK retailers, all normalised to price per 100g so you can compare fairly regardless of bag size or serving suggestion. You will typically pay more per 100g than concentrate, but you are getting significantly more high quality protein per gram of powder.
If budget is your main concern and you tolerate lactose well, whey concentrate may be the better value option. For a completely dairy-free alternative, browse our vegan protein comparison.
Further reading
Shop by goal
Pick a target, see the shortlist.
Brand battles
Two brands, one clear winner.
MyproteinBulk
The UK's two biggest DTC brands, head-to-head
ONMyprotein
Premium global vs budget UK favourite
MyproteinProtein Works
Impact Whey vs Whey 80, cheapest per 25g
Power users
Advanced comparison: every product, filteredDense table view with every product, full filter sidebar, and no editorial surfaces.
Methodology
How we rank every bag.
Independent and transparent. Every price is read from the retailer's own page and checked daily. Here's what goes into each score.
01
Cost normalised to £/25g
Every bag divided by its true protein weight, so you see the real cost of a scoop across any size or brand.
02
Protein density, measured
Protein per 100g from the product's own nutrition panel, so a 90% isolate and a 72% concentrate are never compared on bag price alone.
03
Real prices, checked daily
Prices come from the retailer's own listing, never an RRP, and we re-check them every day rather than leaving a feed to drift.
04
Rankings can't be bought
Rank order is cost per 25g of protein. Some outbound links earn commission, and some Amazon links marked Ad pay per click; none of them buy a position in the table.
Questions, answered.
Whey concentrate contains 70-80% protein with some fat and lactose. Whey isolate is filtered further to 90%+ protein with minimal fat and lactose, making it better for those who are lactose intolerant or want a leaner protein source.
It depends on your goals. If you need higher protein per serving, are lactose intolerant, or are on a calorie-restricted diet, the extra cost can be worthwhile. For general use, whey concentrate offers better value per gram of protein.
The best whey isolate depends on whether you weigh purity, flavour or price most. For pure value, the cheapest option per 25g of protein sits at the top of the table above, with the date each price was checked. Optimum Nutrition Gold Standard Isolate and Bulk Pure Whey Isolate are consistently strong all-rounders, while Isopure is the pick if you need zero carb. Sort by cost per 25g in the grid to see the current best-value isolate.