Warrior Serious Protein 500g
£12.50
Was £17.99
Serious Protein delivers 24g of protein per scoop without the premium price tag.
Made from a blend of soy protein isolate, skimmed milk, casein and glutamine peptides, it has just
107–110 calories, 0.3g fat and no added sugar. The 500g tub gives you 16 servings at just 78p per shake.
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Why We MAde it
Whey prices doubled. Some brands quietly shrank their tubs. Others just raised the price and hoped nobody would notice.
We didn't want to do either. So we looked at what else actually works — and found soy protein isolate, skimmed milk powder, casein and glutamine peptides. Same 24g of protein per scoop. A fraction of the cost.
No hype, no proprietary blend nonsense. Just protein that does the job for 78p a shake instead of what whey costs today.
What's In A Scoop
One 30g scoop. No fluff.
24g
Protein per scoop
107-110
Kcal per serving
0.3g
Fat
0g
Added sugar
78p
Per shake
Is It As Good As Whey?
We're not going to oversell this. Here's the actual evidence.
Soy Scores The Same As Whey On Protein Quality
Soy protein isolate scores 1.0 on the PDCAAS scale — the same top score as whey and casein. PDCAAS (Protein Digestibility-Corrected Amino Acid Score) measures protein quality based on its essential amino acid content and how well the body can digest and use it . A score of 1.0 is the highest possible rating, meaning soy protein isolate is considered a high-quality, complete protein source — just like whey and casein.
Independent Studies Show Equal Muscle & Strength Gains
A meta-analysis pooling 9 separate studies, plus a dedicated randomised controlled trial, both found no meaningful difference in muscle growth or strength gains between soy and whey protein when total protein intake is matched.
No Effect On Testosterone Or Oestrogen
The biggest myth about soy is the hormone one. A pooled analysis across 41 studies and 1,753 men found soy protein has no measurable effect on testosterone or oestrogen levels. (Reed et al. 2021)
Questions? We've Got Answers.
Yes, by the numbers. Soy protein isolate scores 1.0 on the PDCAAS scale — the same top rating as whey. A meta-analysis of 9 studies plus a dedicated RCT found no meaningful difference in muscle or strength gains when protein intake is matched.
No. A pooled analysis across 41 studies and 1,753 men found no measurable effect of soy protein on testosterone or oestrogen levels. (Reed et al. 2021)
Contains soy, milk and gluten (wheat-derived glutamine peptides). Suitable for vegetarians. Not suitable for vegans, those avoiding gluten, or halal requirements.
No added sugar. The 1.4-1.8g of sugar per serving occurs naturally from lactose in the milk powder.
Store in a cool, dry place with the lid sealed tightly after each use. Best used within the timeframe printed on the tub — check the best-before date on your batch.
