How Much Should Protein Powder Cost in the UK?

How much should you pay for protein powder?

For a whey concentrate from a brand you have heard of, £15 to £22 per kilogram is a fair UK price in 2026, which works out at roughly 50p to 72p per 25g of protein. That is the benchmark. Everything below explains where it comes from and where the edges are.

The spread around it is larger than most people expect. WheyWise price checks on 21 August 2026 found mainstream products running from about £9.20 per kilogram at the cheap end to about £34.79 at the expensive end. That is close to a fourfold difference between products that do the same job.

What counts as cheap, fair and overpriced per kg

People search in pounds per kilogram, so here is the honest version in those terms, with the caveat that follows in the next section.

Prices checked 21 August 2026 across the UK retailers we track, using the cheapest publishable variant of each product.

Why price per kilogram is the wrong number

A kilogram of protein powder is not a kilogram of protein. UK whey concentrates typically run 68g to 72g of protein per 100g. Isolates run 80g to 90g. Some plant isolates reach 90g. So a kilogram of one product can contain a third more protein than a kilogram of another at the same shelf price.

Worked example from current prices. Protein Works Whey 360 GOLD is about £19.58 per kilogram at 68g of protein per 100g. Applied Nutrition Critical Whey is about £22.48 per kilogram at 72g. On price per kilogram the Protein Works bag looks 13% cheaper. On cost per 25g of protein they are 72p and 78p, a gap of only 8%. Half the apparent saving was protein density, not price.

This is not a subtlety, it is the whole game, and it is also the position the most upvoted comments in UK protein threads take. The recurring top-voted advice is to check the protein per 100g and aim for 80g as a minimum rather than chasing the lowest sticker price, on the reasoning that some of the really cheap products are cheap for a reason.

One more trap in the same family: judge per 25g of protein, not per scoop. A brand can leave the advertised protein per serving unchanged while reducing protein per 100g, simply by making the scoop bigger. The front of the bag reads the same and every kilogram you buy contains less protein.

The bands that actually matter, per 25g of protein

Monthly figures assume one 25g-of-protein serving a day for 30 days. Prices checked 21 August 2026.

The monthly column is the one worth internalising. The difference between the fair band and the premium band is about £8 a month. The difference between good value and the top of the market is about £20 a month, or £240 a year, for a product that in protein terms is broadly the same.

The good-value band

Pure Source Nutrition PSN Whey Protein Powder

2.5kg bag

The bottom of the credible range, and the number the rest of the market should be judged against. About 32p per 25g of protein at 72g per 100g, checked 21 August 2026, or roughly £10 a month for a daily shake.

Buy PSN Whey Protein Powder →See the price on Amazon

The good-value band

Pure Source Nutrition PSN Whey Protein Powder

2.5kg bag

Pros

• + About £9.20 per kg and 32p per 25g of protein, at the bottom of the whole mainstream range
• + 72g of protein per 100g, identical to Bulk Basic Whey and above Protein Works Whey 360 GOLD at 68g
• + Unambiguously a whey, which not everything at this price point is

Cons

• – No meaningful public review record, so there is nothing to check flavour against before you buy
• – Flavouring is the consistent weak point across this tier of the market

Pros

• About £9.20 per kg and 32p per 25g of protein, at the bottom of the whole mainstream range
• 72g of protein per 100g, identical to Bulk Basic Whey and above Protein Works Whey 360 GOLD at 68g
• Unambiguously a whey, which not everything at this price point is

Cons

• No meaningful public review record, so there is nothing to check flavour against before you buy
• Flavouring is the consistent weak point across this tier of the market

Buy PSN Whey Protein Powder →See the price on Amazon

●Nutrition per scoop · 21.6g protein in 30g▼

Protein makes up 72%

of this 30g scoop · 112 kcal total

21.6g

Protein21.6g

Carbs3g

Fat1.5g

Other3.9g

The recognised-brand band

Bulk Basic Whey Protein

1.25kg bag

The most useful single benchmark on this page. If you are paying more than about 50p per 25g of protein, you should be able to say what you are getting for it.

Buy Basic Whey Protein →Price at BulkView on Amazon ↗

or compare all UK prices →

The recognised-brand band

Bulk Basic Whey Protein

1.25kg bag

Pros

• + About £14.40 per kg and 50p per 25g of protein, which is the good-value band from a brand with a returns policy
• + 72g of protein per 100g, the same as products costing twice as much
• + 2.5kg is a sensible size: enough to get the per-gram price down without committing to 5kg

Cons

• – About 18p a serving more than the cheapest credible whey, which is roughly £5 a month
• – Sits beside Bulk's own Pure Whey at about 95p per 25g, so it is easy to pick the dearer bag by mistake

Pros

• About £14.40 per kg and 50p per 25g of protein, which is the good-value band from a brand with a returns policy
• 72g of protein per 100g, the same as products costing twice as much
• 2.5kg is a sensible size: enough to get the per-gram price down without committing to 5kg

Cons

• About 18p a serving more than the cheapest credible whey, which is roughly £5 a month
• Sits beside Bulk's own Pure Whey at about 95p per 25g, so it is easy to pick the dearer bag by mistake

Buy Basic Whey Protein →Price at BulkView on Amazon ↗

or compare all UK prices →

●Nutrition per scoop · 21.6g protein in 30g▼

Protein makes up 72%

of this 30g scoop · 112 kcal total

21.6g

Protein21.6g

Carbs3.6g

Fat1.2g

Other3.6g

Why isolate costs more, and when it is worth it

Isolate carries roughly 80g to 90g of protein per 100g against 68g to 72g for concentrate, and it is filtered further to strip most of the lactose and fat. That extra processing is real, and it costs real money: European whey protein isolate rose about 59% between October 2025 and July 2026, on top of a base that was already higher than concentrate.

In UK retail terms, expect to pay roughly £1.20 to £1.60 per 25g of protein for an isolate against 50p to 72p for a concentrate. Worth it if you are lactose intolerant or cutting calories tightly. Not worth it otherwise: the protein does the same thing.

Clear whey and diet formats sit above even that, and it is worth being clear that what you are buying there is a format, not better protein. Some products in those ranges pass £2 per 25g of protein.

Does buying a bigger bag actually save money?

Usually. Not always, and the exception is more common than you would think.

Optimum Nutrition is the clearest current counterexample. Checked 21 August 2026, its 2.27kg Gold Standard tub worked out at about £1.40 per 25g of protein while the 896g tub was about £1.10. The bigger tub was roughly 27% more expensive per gram of protein, because those sizes are stocked and priced by different UK third-party sellers rather than by a single price ladder.

So the rule is not "buy bigger", it is "check the per-gram figure on every size". That check takes ten seconds and it is the only way to catch this kind of inversion, which no shelf price will show you.

The other half of the bag-size question is whether you will finish it. A 5kg bag at a great per-gram price is a bad purchase if you abandon it after three weeks because you dislike the flavour. Buy 1kg of anything new.

What UK buyers say they refuse to pay

The community benchmark tracks the data reasonably closely. In UK frugal and fitness discussions through 2026, roughly £11 to £12 per kilogram is the figure people describe as acceptable, around £16 per kilogram gets treated as the tolerable high-street level, and £20 and above draws complaints. One buyer summarised it as being able to live with £11 per kilogram on a 5kg bag.

Worth being careful about how much weight to put on any individual comment, because most of them are unvoted. What is clearly significant is the volume of the conversation: a thread titled "Wheyflation" on the biggest bodybuilding forum drew 351 upvotes and 139 comments in July 2026, which tells you the price change is being felt broadly even if any one price quoted in it is not verifiable.

The pattern in the top-voted replies is consistent, and it is worth repeating because it cuts against the direction most price articles push: the advice that rises is to check protein density and avoid the very cheapest, not to hunt the lowest number.

To see where any specific product sits against these bands, the cheapest protein powder comparison ranks everything by cost per 25g of protein, the protein comparison tool puts any two products side by side, and the protein finder narrows the field if you have not chosen a type yet. For why the benchmark moved in the first place, see what actually drives UK protein powder prices.

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