If you want the best whey protein in the UK for your budget, the real choice is between a whey blend and a whey isolate. Blends such as Applied Nutrition Critical Whey and Naughty Boy Advanced Whey cost less per serving in their larger tubs. Isolates such as BioTechUSA Iso Whey Zero and Applied Nutrition ISO-XP cost a little more and, going by the labels, carry less sugar per scoop. Below we compare all four, plus Reflex and OstroVit, using our product data.
Whey isolate vs concentrate: what is the difference?
Whey concentrate and whey isolate both come from milk. Isolate goes through extra filtering, which removes more of the fat and carbohydrate, including lactose. As a result, isolate usually has a higher share of protein per gram and less sugar per serving.
Concentrate keeps more of the milk fat and carbohydrate, often tastes creamier and is usually cheaper. A blend mixes concentrate with some isolate (and sometimes hydrolysate or milk protein) to land somewhere in between.
Neither type is "better" in general. Both are complete milk proteins, and protein contributes to the growth and maintenance of muscle mass. The right one depends on your budget, how much sugar and fat you want per shake, and how your stomach copes with dairy.
The four main options at a glance
Prices and price per serving are at the time of writing (October 2026) and vary by flavour. Price per serving is the tub price divided by the servings stated for that tub.
| Product | Type | Serving | Protein per serving | Sugars per serving (label) | Tub sizes | Price per serving (Oct 2026) |
|---|---|---|---|---|---|---|
| Applied Nutrition Critical Whey | Blend (concentrate, isolate, hydrolysate, milk protein) | 33 g (2 scoops) | 24 g | Not in our label data | 132 g, 825 g, 2 kg | £0.89–£1.02 (2 kg); £1.20–£1.38 (825 g) |
| Naughty Boy Advanced Whey | Blend (concentrate, milk protein, isolate) | 30 g (1 scoop) | 21 g | 1.9 g (Caramel Biscuit) | 900 g, 2.01 kg | £0.88–£1.01 (2.01 kg); £1.17–£1.35 (900 g) |
| BioTechUSA Iso Whey Zero | Isolate | 25 g (1 scoop) | 21 g | Under 0.5 g (Banana, Chocolate) | 25 g sachet, 454 g, 908 g, 1.816 kg | £1.22–£1.40 (1.816 kg); £1.26–£1.45 (908 g); £1.34–£1.54 (454 g) |
| Applied Nutrition ISO-XP | Isolate (92–98% whey isolate, depending on flavour) | 25 g (1 scoop) | Check the tub label | Not in our label data | 850 g, 1.8 kg | £1.05–£1.21 (1.8 kg); £1.15–£1.32 (850 g) |
Applied Nutrition Critical Whey
Critical Whey is a blend of whey concentrate, whey isolate, whey hydrolysate and milk protein concentrate. A 33 g serving (two scoops) gives 24 g of protein, the highest per-serving figure of the blends here, although the serving is also the largest.
The 2 kg tub works out at roughly £0.89 to £1.02 per serving at the time of writing (October 2026), depending on flavour. There is also an 825 g tub and a four-serving 132 g pouch if you want to try a flavour first. See the full range in our Applied Nutrition collection.
Naughty Boy Advanced Whey
Advanced Whey is also a blend, led by whey concentrate with milk protein concentrate and whey isolate. One 30 g scoop gives about 21 g of protein. The Caramel Biscuit label lists 1.9 g of sugars and 113 kcal per serving.
The 2.01 kg tub is the lowest cost per serving in this guide, at roughly £0.88 to £1.01 at the time of writing (October 2026). Browse more from the brand in our Naughty Boy collection.
BioTechUSA Iso Whey Zero
Iso Whey Zero is a whey isolate. A 25 g scoop gives 21 g of protein, and the Banana and Chocolate labels show under 0.5 g of sugars and about 91–92 kcal per serving. It also has the widest choice of sizes, from single 25 g sachets up to 1.816 kg.
At the time of writing (October 2026), the largest tub costs roughly £1.22 to £1.40 per serving. Note that the standard flavours list a creamer containing skimmed milk powder and a little sugar, so check the label if you avoid either. BioTechUSA also sells Iso Whey Zero Black, which lists 27 g of protein and added creatine in a 30 g serving, and Iso Whey Zero Natural, which uses natural flavourings. More in our BioTechUSA collection.
Applied Nutrition ISO-XP
ISO-XP is a whey isolate with a short ingredient list: whey protein isolate makes up 92% to 98% of the powder depending on flavour (97% in Vanilla), plus flavouring and sweetener. Servings are 25 g. Our product data does not include the protein-per-serving figure, so check the nutrition panel on the tub for the exact amount.
The 1.8 kg tub costs roughly £1.05 to £1.21 per serving at the time of writing (October 2026), which makes it the lowest-cost isolate of the four in its larger size.
Two more worth a look: Reflex and OstroVit
- Reflex 100% Whey is mainly whey concentrate (the Chocolate flavour adds a little isolate). It gives 21 g of protein per 30 g serving, with 1 g of sugars on the Chocolate label. The 2 kg tub works out at about £0.90 per serving at the time of writing (October 2026).
- Reflex Isolate Pro gives 25 g of protein per 30 g serving, with under 0.5 g of sugars on the label and an added digestive enzyme blend. It is about £1.27 per serving for 1.8 kg at the time of writing (October 2026). See the Reflex Nutrition collection.
- OstroVit 100% Whey Protein is a concentrate with 22 g of protein and 2.0 g of sugars per 30 g serving. Its 700 g tub is about £1.75 to £2.01 per serving at the time of writing (October 2026). The brand's unflavoured isolate gives 26 g of protein per 30 g. Find both in our OstroVit collection.
Which should you choose?
- Lowest cost per serving: a large tub of Naughty Boy Advanced Whey or Applied Nutrition Critical Whey. Both come in under about £1.02 per serving in their biggest sizes at the time of writing (October 2026).
- Most protein per scoop from a blend: Critical Whey, at 24 g per 33 g serving.
- Lowest sugar on the label: an isolate such as Iso Whey Zero or Reflex Isolate Pro, both under 0.5 g of sugars per serving.
- Simple ingredient list: ISO-XP, which is mostly whey isolate with flavouring and sweetener.
Not sure? Try an Iso Whey Zero sachet or a Critical Whey 132 g pouch first, as our 14-day returns cover unopened items only. You can compare every option in our protein collection.
FAQ
Is whey isolate better than concentrate?
Not in every way. Isolate usually has more protein and less fat, sugar and lactose per gram; concentrate tends to cost less and taste creamier.
Is whey isolate lactose-free?
Not necessarily. Isolate usually contains less lactose than concentrate, but none of the products here carries a lactose-free statement in our product data. If you need to avoid lactose, check the label or ask your GP or a dietitian.
How much protein is in one scoop?
It depends on the product and serving size: 24 g per 33 g for Critical Whey, 21 g per 30 g for Advanced Whey, 21 g per 25 g for Iso Whey Zero, and 25 g per 30 g for Reflex Isolate Pro.
How long does a tub last?
Divide the servings by how often you have a shake. A 2 kg Critical Whey tub gives 61 servings, so one shake a day lasts about two months.
This guide is for general information and isn't medical advice. Speak to your GP or a pharmacist if you take medication or have a health condition.
