Compare Protein Prices Across 98+ UK Retailers

A buyer's guide to protein prices in the UK

Protein powder is one of the most manipulated supplement categories for pricing. Inflated RRPs, permanent discount codes, inconsistent bag sizes, and varying protein percentages per 100 grams make like-for-like comparison nearly impossible without a tool that normalises everything to the same metric. This guide explains what WheyWise measures, why cost per 25 grams of protein is the only fair ranking metric, and how to use the filters above to find the best value powder for your goals.

Why compare protein prices?

The listed price on a bag of protein powder is close to meaningless on its own. A 2.5 kilogram bag at £30 looks cheaper than a 1 kilogram bag at £15 until you normalise by protein content. The 2.5 kilogram bag may contain whey concentrate at 72 grams of protein per 100 grams; the 1 kilogram bag may be whey isolate at 90 grams per 100 grams. Once you divide the price by the actual protein you get, the cheaper-looking bag often costs more per 25 gram serving.

Brands compound the problem with permanent discount codes. MyProtein lists an Impact Whey RRP that almost never reflects the real selling price. The same is true of Bulk, The Protein Works, and MuscleFood. The displayed RRP is a marketing anchor, not a transaction price. WheyWise pulls the actual checkout price across every retailer and ignores the RRP entirely, which is why the ranking often looks different from what you see on each individual brand site.

The cost per 25 grams of protein metric solves both problems at once. It controls for bag size, protein percentage, and discount timing, and produces a single number you can compare across whey concentrate, whey isolate, vegan blends, casein, and mass gainers without having to run the maths yourself.

How to compare protein prices with WheyWise

The comparison process starts with the category tabs above the ranked product grid. Filter by whey concentrate for the cheapest protein per gram, whey isolate for the purest protein with low fat and lactose, vegan protein for dairy-free options, casein for slow- release before bed, or mass gainer for a calorie surplus stack. Each tab only shows products actually classified in that category, so the ranking stays honest.

Once you have a category, use the budget and size quick filters to narrow by how much you want to spend and how much powder you need. Budget filters work on the total price, size filters work on the bag weight in grams. Both filters compound with category selection so you can find, for example, every whey isolate under £40 in a 1 kilogram bag.

Every product in the filtered set is ranked by cost per 25 grams of protein so the best value sits at the top regardless of brand or bag size. Click any product to see its full price history, retailer breakdown, and the cheapest current option. Brand-specific views like compare MyProtein prices or compare Bulk prices drop you straight onto the ranking for that one brand if you already have a preferred manufacturer.

What we look at to rank every product

Four factors drive every ranking on this page. The primary sort metric is cost per 25 grams of protein. This is the only fair measure across bags of different sizes and protein percentages. Twenty-five grams is roughly one standard scoop of whey isolate, a typical post-workout serving, and the dose at which muscle protein synthesis peaks for most adults. Ranking by cost per 25 grams means a 5 kilogram bag of budget whey concentrate and a 1 kilogram tub of premium isolate can be compared honestly side by side.

The secondary factor is protein percentage per 100 grams. This is the quality indicator. Whey concentrate delivers 70 to 82 grams of protein per 100 grams; whey isolate delivers 85 to 92 grams per 100 grams; vegan blends typically land between 65 and 80 grams per 100 grams. A product below 70 grams per 100 grams is usually a protein blend padded with maltodextrin or added creatine, which is fine for a mass gainer but not for a cutting-phase whey choice.

The third factor is a clean-label score built from ingredient count, presence of artificial sweeteners, and third-party certifications like Informed Sport and Informed Choice. A clean-label score above 80 means the product has a short ingredient list, transparent label, and at least one external purity certification. This matters more for daily long-term users than occasional buyers.

The fourth factor is weekly purchase volume. This is a demand signal that surfaces products people actually re-buy, rather than products that rank well on paper but nobody keeps ordering. Amazon UK review counts, direct-brand Trustpilot scores, and WheyWise click-through data feed the volume signal. A product with a strong cost per 25 grams but no demand signal usually has a hidden problem (taste, texture, availability) that a buyer should know about.

Which protein type offers the best price?

Whey concentrate is consistently the cheapest protein type per 25 grams in the UK. Budget brands like MyProtein Impact Whey, Bulk Pure Whey, and The Protein Works Whey Protein 80 land between 30 and 50 pence per 25 gram serving on standard sale pricing. These products deliver 72 to 82 grams of protein per 100 grams at the cost tier most recreational lifters should start from. See the full whey concentrate comparison for live rankings.

Whey isolate costs more per bag due to the additional filtration process, but delivers 85 to 92 grams of protein per 100 grams so the cost per 25 grams is closer to concentrate than the sticker price suggests. Applied Nutrition ISO-XP and Bulk Pure Whey Isolate typically land between 60 and 90 pence per 25 gram serving. Whey isolate is the right pick for lactose-sensitive users, GLP-1 medication users (Mounjaro, Wegovy) who need low-carb protein, and cutting-phase lifters watching calories.

Vegan protein has closed the price gap significantly in 2025 and 2026. Pea and soy blends now compete directly with mid-range whey at 50 to 75 pence per 25 gram serving. Bulk Vegan Protein and The Protein Works Vegan Protein 360 are the two most consistent UK picks. Expect a slightly grainier texture and earthy aftertaste compared to whey, but the gap is much narrower than it was in 2020.

Casein and mass gainers serve different goals and should not be compared to whey on cost per 25 grams alone. Casein is slow-digesting and priced for a pre-bed niche; mass gainers load carbs alongside protein for weight gain rather than cutting. If you are comparing across a 5 kilogram bag for bulk efficiency, the cheapest way to buy protein powder in the UK covers bulk purchasing, flash sales, and the hidden cost of brand loyalty.

Common questions beyond the table

Best price whey protein UK: the cheapest whey at any given moment changes weekly as MyProtein, Bulk, and The Protein Works rotate their flash-sale schedules. The ranking above surfaces whichever product is cheapest per 25 gram dose right now; the full cheapest protein powder UK list shows the top ten on a dedicated view.

Cheap protein powder 5kg and bulk sizes: 5 kilogram bags typically cost 10 to 20 percent less per 25 gram dose than 1 or 2 kilogram bags. This is the single largest saving available on protein powder. MyProtein Impact Whey and Bulk Pure Whey both offer 5 kilogram bags; the size filter above lets you show only bulk sizes across the whole ranking.

Protein powder deals UK: the dedicated WheyWise deals page ranks every active voucher code and flash sale across UK retailers, sorted by how deep the discount is. Codes are refreshed every six hours; most deal pages elsewhere on the internet list codes that expired months ago.

Whey protein price per kg: price per kilogram is a common comparison metric but it is less accurate than cost per 25 grams of protein because it ignores protein percentage. A 1 kilogram bag of 90 percent isolate at £35 delivers 900 grams of actual protein for £35; a 1 kilogram bag of 72 percent concentrate at £25 delivers 720 grams of protein for £25. The isolate looks pricier per kilogram of powder but costs less per kilogram of protein (£38.89 vs £34.72). Cost per 25 grams fixes this across every category on the page.

Best value protein powder UK 2026: the top of the ranking table is the answer to this query in real time. As of April 2026, Bulk Pure Whey, MyProtein Impact Whey, and The Protein Works Whey Protein 80 trade the top three positions on most weeks depending on sale cycles. The ranking is refreshed every Friday and reflects pulled prices from the previous 24 hours.

Protein powder price history: every product page on WheyWise shows the cheapest historical price across all tracked retailers. If a brand advertises a 40 percent discount, you can verify whether that is a genuine price drop or a permanent inflated-RRP play. This is the single fastest way to spot a fake sale and it applies to every one of the 3,403 products tracked on this page.

Questions, answered.