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Myprotein Slow-Release Casein vs Optimum Nutrition Gold Standard 100% Whey

The published reviews of Myprotein Slow-Release Casein and Optimum Nutrition Gold Standard 100% Whey, lined up: the five scores, what one serving delivers against the studied dose, the real cost per serving and what each label leaves out. Figures as of 28 September 2026.

The short answer

Myprotein Slow-Release Casein scores 7.6/10 against Optimum Nutrition Gold Standard 100% Whey's 7.0. The widest gap is value against the generic equivalent: 8 for Myprotein Slow-Release Casein, 5 for Optimum Nutrition Gold Standard 100% Whey.

Pick Myprotein Slow-Release Casein if…

  • you want better value against the plain generic version
  • you want every amount on the label disclosed

Pick Optimum Nutrition Gold Standard 100% Whey if…

  • you want the stronger evidence behind what it is sold to do
  • you want a serving that matches the amount used in research

Criterion by criterion

The five criteria every review is scored on, published on the grading page. The overall score is their average.

Evidence for the marketed claim

How strong the research is for what the product is actually sold to do — not for the ingredient in general.

Myprotein Slow-Release Casein7/10
Optimum Nutrition Gold Standard 100% Whey8/10Leads

Dose against the studied amount

Whether one serving delivers the amount used in the research behind the claim.

Myprotein Slow-Release Casein7/10
Optimum Nutrition Gold Standard 100% Whey8/10Leads

Label transparency

Whether the Supplement Facts panel is published in readable text and every active amount is disclosed.

Myprotein Slow-Release Casein8/10Leads
Optimum Nutrition Gold Standard 100% Whey6/10

Value against the generic equivalent

Cost per gram or per dose of the active ingredient, compared with the plainest version of the same thing.

Myprotein Slow-Release Casein8/10Leads
Optimum Nutrition Gold Standard 100% Whey5/10

Safety and tolerability

Known risks and interactions, how well characterised they are, and whether the label warns about them.

Myprotein Slow-Release Casein8/10
Optimum Nutrition Gold Standard 100% Whey8/10

Dose against the studied amount

What one labelled serving delivers, placed against the range on each ingredient’s evidence page. Where a label gives no figure, there is nothing to place, and that is the finding.

Whey protein blendEvidence A

Where muscle protein synthesis maxes out: 20–25 g a dose

  • Myprotein Slow-Release CaseinNot in the formula
  • Optimum Nutrition Gold Standard 100% Whey24 g protein per 30 g servingIn range

What it actually costs

Price divided by labelled servings, from a dated listing. A serving is whatever the label calls one, which is why the studied-dose row matters more than the headline figure.

  • Myprotein Slow-Release CaseinAbout £23.95–£41.99 for 1 kg and £48.99 for 2.5 kg at UK retailers in listings read on 28 September 2026. No per-serving figure: servings not recorded.
  • Optimum Nutrition Gold Standard 100% Whey£39.99–£50.00 across seven UK retailers, checked 22 September 2026. No per-serving figure: servings not recorded.

Label checks

What each label discloses, and what it leaves out. Read from the reviews, not from the marketing.

Myprotein Slow-Release Casein

  • Every active ingredient has a stated amount
  • No third-party certification

Optimum Nutrition Gold Standard 100% Whey

  • 2 of 3 listed ingredients have no stated amount
  • No third-party certification

How this comparison is built

  • Scores are the ones already published in each review. Nothing is re-scored for the comparison, and a product leads a criterion only when it outscores the rest.
  • Doses are read from the label rows in each review and placed against the studied range on the matching ingredient page. A figure that is not printed is never estimated.
  • Costs use a dated retailer price divided by labelled servings. Prices in different currencies are never ranked against each other.
  • Only products in the same category, or ones a review names as an alternative, can be compared. Commission never changes what appears here.

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