The UK protein powder market is enormous — hundreds of products, dozens of retailers, and prices that change weekly. Whether you are looking for a whey protein powder to mix into a quick protein shake after training, or a vegan protein powder with a solid amino acid profile, there is no shortage of choice. This guide cuts through the noise. I've compared the most popular options on price per 100g, protein content, and availability across major UK retailers.
One note before we start: this isn't a taste test or a lab analysis — it's a price and value comparison. For what it's worth, I've tried most of these personally, but your palate is different to mine. What I can tell you objectively is which products give you the most protein per pound, which matters if you are serious about hitting your daily protein intake for muscle building or general health.
Best overall value: MyProtein Impact Whey
MyProtein Impact Whey consistently comes out cheapest per 100g, especially during their frequent sales (which is most of the time, honestly). At roughly £1.40–1.60/100g on sale, it's hard to beat. The protein content is solid at around 82g per 100g — meaning each serving delivers a strong hit of essential amino acids for muscle repair and recovery after intense exercise. There are dozens of flavours, making it easy to keep your post workout protein shake interesting.
The main downside is that the "real" price versus sale price is a bit of a game — the listed price is inflated so the constant discount looks bigger. Use the per-100g price as your benchmark, not the percentage off.
MyProtein Impact Whey Protein Powder
810g bag
UK's bestselling whey concentrate with 82g protein per 100g. Regularly discounted 40-60% — never pay full price.
See cheapest price →Buy direct from MyProtein →MyProtein Impact Whey Protein Powder
810g bag
UK's bestselling whey concentrate with 82g protein per 100g. Regularly discounted 40-60% — never pay full price.
See cheapest price →Buy direct from MyProtein →Quick verdict
Pros
- + 82g protein per 100g high purity
- + Cheapest per serving during sales
- + Huge 60+ flavour range
- + 5kg bags for long-term savings
Cons
- – Full price is poor value
- – Needs discount code to compete
- – Reformulations change taste occasionally
Quick verdict
Pros
- + 82g protein per 100g high purity
- + Cheapest per serving during sales
- + Huge 60+ flavour range
- + 5kg bags for long-term savings
Cons
- – Full price is poor value
- – Needs discount code to compete
- – Reformulations change taste occasionally
Best runner-up: Bulk Pure Whey Protein
Bulk is MyProtein's closest competitor on price. Their Pure Whey Protein sits at around £1.50/100g and the quality is comparable. The protein is sourced from the same type of grass-fed whey concentrate, delivering a similar amino acid profile. Some people prefer the taste of Bulk's flavours — particularly the vanilla, which is less artificial-tasting than MyProtein's.
Bulk also runs regular sales and has a good selection of sizes from 500g up to 5kg. If you are trying to build muscle mass on a budget, Bulk is one of the most reliable options for keeping your protein intake high without overspending.
Bulk Pure Whey Protein
2.5kg bag
Budget-friendly Informed Sport tested whey from Bulk with 50+ flavours. Consistently among the cheapest per serving in the UK.
See cheapest price →Buy direct from Bulk →Bulk Pure Whey Protein
2.5kg bag
Budget-friendly Informed Sport tested whey from Bulk with 50+ flavours. Consistently among the cheapest per serving in the UK.
See cheapest price →Buy direct from Bulk →Quick verdict
Pros
- + Among cheapest UK whey options
- + Huge 50+ flavour range
- + 22g protein per 30g scoop
- + Informed Sport batch tested
Cons
- – 70-75% protein purity only
- – Some flavours overly artificial
- – Can cause bloating if lactose-sensitive
Quick verdict
Pros
- + Among cheapest UK whey options
- + Huge 50+ flavour range
- + 22g protein per 30g scoop
- + Informed Sport batch tested
Cons
- – 70-75% protein purity only
- – Some flavours overly artificial
- – Can cause bloating if lactose-sensitive
Best isolate: MyProtein Impact Whey Isolate
If you're lactose intolerant or want a cleaner macro profile, whey isolate is worth the premium. MyProtein's isolate sits at around £2.50–3.00/100g, which is roughly double the concentrate — but the protein content is higher (around 90g/100g) and it's lower in fat and carbs. The higher concentration of essential amino acids makes it a popular choice as a post workout protein boost, especially for people doing intense exercise who want rapid absorption. Compare all whey isolate prices to find the cheapest right now.
MyProtein Impact Whey Isolate Powder
1kg bag
Protein powder from MyProtein. Compare prices across UK retailers.
See cheapest price →Buy direct from MyProtein →MyProtein Impact Whey Isolate Powder
1kg bag
Protein powder from MyProtein. Compare prices across UK retailers.
See cheapest price →Buy direct from MyProtein →Quick verdict
Pros
- + Very high protein content
- + Low fat, fast absorbing
Cons
- – Premium price point
Quick verdict
Pros
- + Very high protein content
- + Low fat, fast absorbing
Cons
- – Premium price point
Best premium option: Optimum Nutrition Gold Standard
ON Gold Standard is the global benchmark for a reason. It's not cheap — typically £2.20–2.50/100g — but the consistency and quality are excellent. If you buy via Holland & Barrett during a 3-for-2 or buy-one-get-one event, the effective price becomes much more competitive.
Optimum Nutrition Gold Standard 100% Whey Protein Powder
900g bag
Protein powder from Optimum Nutrition. Compare prices across UK retailers.
See cheapest price →Buy direct from Optimum Nutrition →Optimum Nutrition Gold Standard 100% Whey Protein Powder
900g bag
Protein powder from Optimum Nutrition. Compare prices across UK retailers.
See cheapest price →Buy direct from Optimum Nutrition →Quick verdict
Pros
- + Very high protein content
- + Widely available in the UK
Cons
- – Premium price point
- – Contains lactose
Quick verdict
Pros
- + Very high protein content
- + Widely available in the UK
Cons
- – Premium price point
- – Contains lactose
Best budget pick: Protein Works Whey Concentrate 80
Protein Works often flies under the radar but their whey concentrate regularly comes in under £1.60/100g on sale with a discount code. The flavour selection is decent and the quality is consistent.
The Protein Works Whey Protein 80 - BLACK Innovation
2kg bag
Protein powder from The Protein Works. Compare prices across UK retailers.
See cheapest price →The Protein Works Whey Protein 80 - BLACK Innovation
2kg bag
Protein powder from The Protein Works. Compare prices across UK retailers.
See cheapest price →Quick verdict
Pros
- + Frequently on sale great deals
- + 80% protein purity decent
- + Massive 40+ flavour menu
- + Smooth mixability with water
Cons
- – Full price is above average
- – Sweetness overpowering some flavours
- – Taste can vary between batches
Quick verdict
Pros
- + Frequently on sale great deals
- + 80% protein purity decent
- + Massive 40+ flavour menu
- + Smooth mixability with water
Cons
- – Full price is above average
- – Sweetness overpowering some flavours
- – Taste can vary between batches
How to actually compare
Don't compare total prices — compare price per 100g. A 2.5kg bag looks expensive next to a 1kg bag, but it's almost always cheaper per gram. Use the protein powder price comparison to see current prices across all retailers sorted by per-100g cost. You can also browse by type — whey concentrate, whey isolate, or vegan protein.
Also factor in any active discount codes — a 25% off code can make a seemingly expensive retailer the cheapest option overnight. Check the protein powder discount codes for today's best offers, or read MyProtein vs Bulk: which is cheaper? for a head-to-head breakdown.
How to choose the right protein powder
With so many options on the market, picking the right protein powder comes down to a few practical questions. First, consider your goals. If you are focused on muscle building after intense exercise, a whey protein powder with a complete amino acid profile — rich in essential amino acids like leucine — is the most effective choice. If you follow a plant-based diet, vegan protein powders made from pea, rice, or hemp blends can still deliver the plant proteins you need, though the amino acid profile is usually less complete per serving.
Next, think about when you will use it. A quick protein shake mixed with water is the simplest post workout option, but protein powder also works well blended into porridge, smoothies, or baking. The versatility makes it easier to hit your daily protein target as part of a balanced diet — especially if you struggle to get enough from whole foods alone. Government guidelines suggest most adults need around 0.75g of protein per kilogram of body weight, but anyone doing regular resistance training will likely benefit from a higher protein intake in the range of 1.6–2.2g per kilogram to support muscle mass and muscle repair.
Finally, do not overthink it. The difference between a good whey concentrate and a premium isolate matters less than consistency. Pick a product you can afford to buy every month, that you actually enjoy drinking, and that fits your macros. A protein boost from any reputable brand on this list will support your goals — the best protein powder is the one you will actually use. If you are not sure where to start, use the comparison tool to sort by price and find the cheapest option that matches your needs.
