Overview
Serious Protein sells one thing above all: quantity. A 4kg bag for under forty pounds works out at some of the cheapest protein per serving you can buy in the UK, aimed at high-volume users who care more about hitting daily protein than about gourmet flavour. The 3.9 rating from around 1,300 buyers is honestly mixed by protein-powder standards, and the pattern in reviews is consistent: praised for value and macros, marked down on taste and mixability. Here is the full picture.
At a glance - Size
- 4kg bag (very high servings per bag)
- Best for
- Budget-first, high-volume protein users
- Macros
- Low carb, lean-muscle focused blend
- Rating
- 3.9 / 5 from ~1,300 reviews (mixed)
- Weak spot
- Taste and mixability, per many reviewers
- Typical price
- Under £40 for 4kg (check live price below)
What you are actually buying
This is a value play, plain and simple. Four kilograms of low-carb protein powder for less than many brands charge for one kilogram puts Serious Protein among the cheapest per-serving options on Amazon UK. For someone drinking one or two shakes a day, a bag this size can last months, which is exactly the point.
The formula targets lean muscle support and recovery with a low-carb profile, which suits cutting phases and anyone watching sugars. It is a workhorse product, not a treat.
The honest catch: a mixed 3.9 rating
We do not dress up ratings: 3.9 is below what good protein powders score, and the review pattern explains why. Buyers consistently praise the value and the macros, and consistently criticise the taste (often described as bland or artificial) and the mixability, with some reporting clumping in water. Flavour satisfaction also varies noticeably between the options.
None of that makes it a bad product; it makes it a trade-off. If you drink shakes quickly with milk or blend them into porridge or smoothies, taste matters less and the value shines. If your shake is something you savour, a 3.9-rated budget bag will probably disappoint you.
Verdict: who should buy it, who should not
Buy Serious Protein if you are optimising for cost per gram of protein, get through a lot of powder, and are happy to mask the flavour in milk, oats or a blender. It is one of the cheapest ways in the UK to hit a high protein target. Skip it if taste and easy mixing rank alongside price for you: a mid-price bag from a better-rated brand (typically scoring 4.3 and up) costs more per serving but is far more pleasant daily. Whichever way you go, check the live price below, as big bags fluctuate often.
Key features, as the manufacturer lists them
Taken from the product listing via Amazon's product API. These are the seller's claims, not our test results.
- HIGH-PROTEIN SHAKE FOR DAILY MUSCLE SUPPORT – Each serving of The Bulk Protein Company's SERIOUS PROTEIN provides 24g of complete protein from a blend of milk protein concentrate and soy protein isolate, supporting muscle repair, recovery and everyday strength goals. Ideal for post-workout shakes, high-protein diets, meal prep or maintaining lean muscle. Mixes best in a shaker or blender for a smoother, more satisfying protein drink you can enjoy anytime.
- BLENDED PROTEIN DRINK FORMULA FOR BETTER ABSORPTION & BALANCE – A high-protein blend made with milk protein concentrate, soya protein isolate and glutamine peptides to support steady muscle repair, recovery and strength throughout the day. This bulk 4kg protein powder offers over 133 servings, giving excellent value for daily high protein shakes, high-protein diets, meal prep and maintaining lean muscle goals while fitting easily into any fitness routine.
- LOW-CALORIE, EVERYDAY PROTEIN FOR MEN & WOMEN – A high-quality protein blend designed with low carbs, low sugar and low fat to support lean goals, weight management and active lifestyles. Ideal for high-protein diets, cutting phases, gym training and daily fitness routines, offering a simple way to increase protein intake without unnecessary calories. Perfect for adding into shakes, smoothies, oats or high-protein meal prep.
- DELICIOUS FLAVOURS WITH A SMOOTHER, MORE BALANCED TASTE – Available in Banana, Choc Peanut Butter, Chocolate, Cookies & Cream, Salted Caramel and Strawberry, this protein powder delivers a clean, enjoyable flavour without overpowering sweetness or strong artificial aromas. Ideal for daily protein shakes, smoothies, oats or high-protein recipes, giving you flexible ways to enjoy each flavour in your routine.
- EASY-MIX SHAKE WITH IMPROVED TEXTURE & CONSISTENCY – Designed for smoother mixing, this high-protein blend works best in a shaker with a mixer ball or a blender to help reduce clumps and gritty texture. Many customers enjoy the creamy consistency when mixed with water or milk, making it ideal for daily protein shakes, meal replacement shake, pre workout powder, post-training recovery, meal prep or adding extra protein to oats, smoothies and high-protein recipes.
Frequently asked questions
Is Serious Protein any good?
It depends what you value. For price per serving it is excellent, which is why high-volume users buy the 4kg bag. Its 3.9 rating is honestly mixed though: reviewers praise value and macros but often criticise taste and mixability. It is a value workhorse, not a premium powder.
Why is the rating only 3.9?
The recurring criticisms in reviews are taste (bland or artificial to some) and mixability (clumping in water for some buyers), while the price and low-carb macros are consistently praised. Ratings for budget big-bag proteins usually sit below premium brands for exactly these reasons.
How can I make budget protein taste better?
Mix with milk instead of water, use a blender or shaker ball, add a banana or coffee, or stir it into porridge or yoghurt. Most taste complaints soften considerably when the powder is blended rather than shaken with water alone.
Is a 4kg bag worth it?
If you already know you tolerate and accept the flavour, the per-serving saving of a 4kg bag is significant. If you have never tried the brand, buying a smaller size first (or a better-rated mid-price powder) is the safer move, because 4kg of a flavour you dislike is a long commitment.
Check price on Amazon →
