At a Glance
| Metric | Gold Standard 100% Whey | Impact Whey Protein |
|---|---|---|
| FitLab Score | 9.8/10 | 8.5/10 |
| Protein per scoop | 24g | 21g |
| Calories | 120 cal | 103 cal |
| Leucine per scoop | 2.7g | 1.9g |
| Protein type | WPI + WPC | WPC-80 only |
| Price (sale) | $0.88/serving | $0.78/serving |
| Price (full) | $0.88/serving | $1.10–$1.30/serving |
| Third-party cert | Informed Sport ✅ | None ✗ |
| Banned substance test | Yes | No |
| Flavours | 20+ | 80+ |
| Batch consistency | High | Variable |
Leucine Gap — The Hidden Difference
The most important difference between these proteins isn't price or brand — it's leucine content. Gold Standard Whey delivers 2.7g leucine per scoop. Impact Whey delivers approximately 1.9g. The minimum threshold to maximally activate mTORC1 for muscle protein synthesis is 2.5g leucine.
This means a single scoop of Impact Whey (21g protein) provides sub-threshold leucine. The practical fix: take 1.5 scoops (31.5g protein, ~2.85g leucine) post-workout. This reduces the cost advantage. Alternatively, mix Impact Whey with a leucine-rich food post-workout (chicken, eggs, yoghurt) to hit the threshold from combined sources.
When MyProtein Wins — The Sale Math
MyProtein runs 35–50% discount events almost every month. At 35% off, a 2.5kg bag of Impact Whey costs approximately $0.78/serving — the best protein value available. At this price, even accounting for the 1.5-scoop adjustment, the cost per optimal serving (~$1.17) is still lower than Gold Standard at full price.
The critical caveat: you must buy on sale. MyProtein at full price ($1.10–1.30/serving) is worse value than Gold Standard in every dimension. If you're disciplined enough to stock up during sales (typically Black Friday, January, and monthly flash sales), Impact Whey in the 2.5–5kg size is genuinely compelling.
Certification — Non-Negotiable for Some
Gold Standard Whey carries Informed Sport certification — every production batch tested for 280+ banned substances. MyProtein carries no equivalent certification. For athletes competing under WADA, USADA, UKAD, or any national federation drug testing programme, this isn't a preference — it's mandatory.
For recreational gym-goers with no drug testing, certification is a quality signal rather than a requirement. Gold Standard's certification also gives meaningful confidence in label accuracy — the protein content you see is the protein content you get.
Gold Standard 100% Whey wins — but Impact Whey Protein is better for some buyers
On sale, MyProtein Impact Whey at $0.78/serving is exceptional value. Off sale, Gold Standard wins on every dimension. The decision: if you're disciplined about buying MyProtein only during 35%+ sales and you're lactose tolerant — Impact Whey wins on cost. If you need certification (drug-tested sport), consistent quality, or buy protein irregularly — Gold Standard Whey every time.
Frequently Asked Questions
Yes — it's a legitimate WPC-80 product with real protein at a competitive price. The limitations are: lower leucine per scoop (compensated by taking 1.5 scoops), no third-party certification, and batch-to-batch flavour inconsistency. For budget-conscious buyers who buy on sale, it's excellent value.
There are no credible lab tests showing amino spiking in MyProtein's Impact Whey line. The protein content is lower per scoop (21g) because they use WPC-80 — a 80% protein concentrate — rather than WPI. Lower protein count per scoop is not the same as amino spiking.
Both work well for beginners. MyProtein's 80+ flavours make it easier to find something you enjoy, which matters for consistency. Gold Standard has a higher quality floor and is more widely available in physical stores. If cost is the priority: MyProtein on sale. If convenience: Gold Standard.
Almost every month. Major events: January sale, Black Friday, student discount periods, and various flash sales. Subscribe to their email list and buy 2.5–5kg bags when the discount hits 35%+ — this is the correct strategy for MyProtein.
Whey protein isolate (WPI) undergoes further filtration than concentrate (WPC), removing more fat and lactose and concentrating protein to 90%+ purity. Gold Standard Whey uses WPI as the primary source. Impact Whey uses WPC-80 (80% protein). WPI is slightly faster absorbing and lower in lactose, but at matched protein doses, muscle-building outcomes are equivalent.
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