Quick answer
Any price comparison site should be willing to answer a simple question: where does the data actually come from? Here is the honest version for ProteinDeals.
Weekly automated price tracking
A script runs once a week and visits the product pages of every tracked retailer. It reads the current price, checks whether the item is in stock, and stores both in a database. That database is what powers the comparison table on this site.
The check runs in the early hours UK time, so prices here reflect roughly the previous night's data. If a retailer changes a price in the afternoon, it will not appear here until the following morning's run.
Price per 100g normalisation
Raw prices are close to useless for comparison. A £30 bag of 1kg and a £50 bag of 2.5kg cannot be compared fairly without doing the maths first. ProteinDeals converts every price to a cost per 100g, which is the only figure that actually matters for judging value.
The formula is simple: (price ÷ weight in grams) × 100. Where a product has an active discount code, the post-code price per 100g is calculated and shown alongside the original.
Which retailers are tracked
Coverage currently includes the main UK retailers: MyProtein, Bulk, Optimum Nutrition via Amazon UK and Holland & Barrett, Protein Works, PhD Nutrition, and several others. The list grows over time, usually after someone asks why a particular retailer is missing.
Community perspective
What others are saying
Yeah, I think most people don't realise how cheap non ultra processed meat is relative to other products in the UK compared to other european countries. It's so easy to have a protein filled diet here.
u/Reoclassic in r/UK_Food
I don't foresee it ever going on sale, the per serving price is very low for the quality of protein. I do wish they made a vanilla though.
u/Hackanddash in r/Costco
Anecdotes are useful for spotting recurring taste, texture and convenience issues, but they are not evidence of effectiveness.
Discount codes
Retailers frequently run discount codes, especially MyProtein and Bulk. Where an active code is known, it is stored alongside the product and used to calculate an effective price. The code appears next to the price and can be copied with one click.
There is no fully automated way to discover new codes yet. They are added manually when spotted or sent in by readers. If you know of a code that is not showing, get in touch and it will be added.
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When prices differ from what you see at checkout
This happens occasionally, for a few reasons: the price changed after the last update ran, the retailer is showing a different price based on account or location, or the fetch hit a cached page. Always check the final price at checkout before buying, since that is the number that actually counts.
If a price is consistently wrong rather than just briefly out of date, that points to a tracking issue. Report it via the contact page and it will be fixed.
What isn't tracked
Protein bars, ready-to-drink shakes, creatine, BCAAs, and other supplements sit outside scope for now. This tracker is specifically for protein powder. Even within that, flavour availability varies, since not every flavour of every product is tracked, only the most common ones.
To see exactly what is tracked and compare live prices, visit the price comparison table. For a breakdown of which products deliver the best value, see cheapest protein per gram in the UK.
