Every product on this site is assessed against the same structured framework, built from six weighted categories: testing & evidence, ingredient/formulation quality, value, dose transparency, manufacturer transparency and label transparency.
The weight given to each category is published below and can vary slightly by supplement type - oxidation testing matters more for a fish oil than a creatine powder, for instance - but the underlying six categories and the principle behind them never change: we score what is actually disclosed and verifiable, not what a listing merely claims.
Affiliate relationships never influence a score. A product does not get a higher rating for paying a higher commission, being a Prime-eligible listing, or being easier for us to source - see our Affiliate Disclosure for how those links work.
Full detail on how each category is calculated is on our How We Score Products page, and on how we assess testing evidence specifically on How We Verify Testing.
Our current scoring framework
Scores combine six categories. We normalise the weights to a total of 100. A supplement may have a category-specific weighting; its product analysis displays the actual breakdown.
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Daily cost divides the price by the number of days supplied at the label serving. Tables show daily cost alongside the relevant active amount. Some categories also use a comparable-unit calculation in their value score, such as cost per 100 mg elemental magnesium; the product analysis explains the category basis. Missing amounts are shown as unavailable.
A high score is not a medical recommendation. Price convenience, Prime status and affiliate commission do not establish quality or individual suitability.
What our picks mean
Best Overall uses the highest overall score in the current comparison. Cheapest Per Day uses the lowest disclosed daily cost among eligible products. Best Tested uses the highest testing-evidence score among eligible reviewed products with supporting evidence; its badge identifies whether that evidence is a claim, a manufacturer report or independently verified evidence. Ties use overall score, then product ID. Each award is ranked independently, so the same product can win more than one. No testing award is assigned if qualifying evidence is unavailable.
We keep testing claims distinct from independently checked evidence and show provenance where it is recorded.