How We Score Products

Every rating on this site is produced by the same five-criteria rubric. It is published here so you can check our arithmetic.

The five criteria

Each product is scored from 1 to 5 on five criteria. The criteria are weighted, because they are not equally important: what is in a product and whether it has been tested matter more than how long the refund window is.

25%
Ingredient transparency editorial Whether the label discloses how much of each ingredient it contains, rather than hiding amounts inside a proprietary blend.
25%
Strength of evidence editorial Whether the finished product has been tested in a published trial, or the claims rest on research into individual ingredients.
20%
Value for money calculated Monthly cost at the single-unit price, compared against the rest of the category.
15%
Guarantee terms calculated Length of the refund window measured against the trial period the vendor itself recommends.
15%
Buying experience editorial How the product is sold: sales channel, checkout upsells, subscription defaults and how clearly the offer is presented.

Calculated vs editorial

Two of the five criteria are calculated directly from the product's own data and involve no opinion at all. Value is derived from the single-unit monthly price, and guarantee from the length of the refund window. They update automatically whenever a price or guarantee changes, so they cannot drift out of date.

The remaining three are editorial judgements. Every product page shows a “Why these scores” note explaining the reasoning behind its own, so you can disagree with us on the specifics rather than having to take a number on trust.

Scores are comparative

Scores rank products against others in the same category, not against a theoretical ideal. That matters, because some limitations apply to almost every product we review:

  • Doses are rarely disclosed. Most of these products use proprietary blends that list ingredients without amounts, so there is usually no way to check them against the quantities used in research.
  • Finished formulas are almost never trialled. Where research is cited, it is nearly always on individual ingredients studied in isolation, not on the product as sold.
  • They are sold through a single channel. Direct-response supplements are typically available only from the manufacturer's own site, so there is no retail price to compare against, and checkouts usually push multi-unit upsells.

If we scored against an ideal product, every item here would land in a narrow band near the bottom and the rating would tell you nothing useful. Instead we score them against each other and state the shared limitations plainly — here, and in the cons on every review.

What the scores mean

Excellent
4.5+
Strong
4.0+
Decent
3.5+
Mixed
3.0+
Weak
2.5+
Poor
Below 2.5

We do not grade on a curve to make products look good. At the time of writing, no product on this site scores above 4.5, and several sit below 3. A rating that never dipped below 4.5 would be worthless to you, and we would rather publish a number you can act on.

How this affects what we earn

We earn a commission when a reader buys through a link on this site, and that is disclosed on every page. It does not feed into the rubric: none of the five criteria is affected by what a product pays, and products that score poorly keep their poor score. See our affiliate disclosure and editorial policy.

Corrections

If a manufacturer publishes dose information, a trial appears, or a price or guarantee changes, the score changes with it. If you think we have a criterion wrong on a specific product, tell us via the contact page and we will review it.

See all scored reviews →