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Myprotein Impact Vegan Protein vs Optimum Nutrition Gold Standard 100% Casein Protein Powder

The published reviews of Myprotein Impact Vegan Protein and Optimum Nutrition Gold Standard 100% Casein Protein Powder, 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 Impact Vegan Protein scores 8.2/10 against Optimum Nutrition Gold Standard 100% Casein Protein Powder's 6.6. The widest gap is value against the generic equivalent: 9 for Myprotein Impact Vegan Protein, 5 for Optimum Nutrition Gold Standard 100% Casein Protein Powder.

Pick Myprotein Impact Vegan Protein if…

  • you want better value against the plain generic version
  • you want every amount on the label disclosed
  • you want the stronger evidence behind what it is sold to do

Pick Optimum Nutrition Gold Standard 100% Casein Protein Powder if…

It does not lead on any criterion we score. Read its review for the case in its favour.

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 Impact Vegan Protein8/10Leads
Optimum Nutrition Gold Standard 100% Casein Protein Powder7/10

Dose against the studied amount

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

Myprotein Impact Vegan Protein8/10Leads
Optimum Nutrition Gold Standard 100% Casein Protein Powder7/10

Label transparency

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

Myprotein Impact Vegan Protein8/10Leads
Optimum Nutrition Gold Standard 100% Casein Protein Powder6/10

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 Impact Vegan Protein9/10Leads
Optimum Nutrition Gold Standard 100% Casein Protein Powder5/10

Safety and tolerability

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

Myprotein Impact Vegan Protein8/10
Optimum Nutrition Gold Standard 100% Casein Protein Powder8/10

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 Impact Vegan ProteinAbout £19.99–£24.99 for 1 kg on Myprotein’s UK store and £42.99 for 2.5 kg on a UK price comparison site, in listings read on 28 September 2026. No per-serving figure: servings not recorded.
  • Optimum Nutrition Gold Standard 100% Casein Protein PowderAbout £36.95–£38.95 for the 924 g tub and £55.79–£64.99 for the 1.8 kg at UK retailers in search listings on 28 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 Impact Vegan Protein

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

Optimum Nutrition Gold Standard 100% Casein Protein Powder

  • Every active ingredient has a 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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