Beauty ingredients and formulas, verified.

The working ingredient in a skincare product is a commodity. Vitamin C is vitamin C; niacinamide is niacinamide. What differs between a $9 serum and a $90 one is usually not the molecule but the concentration, the packaging, and the margin — and the industry has arranged things so you cannot easily tell which. Most brands do not print how much of the active is in the bottle, and the ones that do rarely make it easy to compare.

So we do the comparison. For every active we cover, we read the primary literature and record what concentration actually works, at what pH, with what evidence behind it, and who should avoid it — each claim linked to a specific study, verified against PubMed before it ships. For every product, we take the published INCI list, match each ingredient against the EU CosIng register, confirm the active is genuinely present and high enough in the list to matter, and compute the price per gram of the active. That last number is the one the marketing never gives you, and it is the whole point: it converts "expensive" and "effective" from synonyms back into two separate questions.

The result is 44 actives, 125 products with verified ingredient lists, and 41 dupe reports that ask one question — is the cheap one actually the same formula? — and answer it with the labels rather than with vibes. Sometimes the answer is no. The reports say so, because a dupe verdict that always finds a dupe is worth nothing.

We also publish what the evidence doesn't show. Where a benefit is in-vitro only, where a trial was small or funded by the manufacturer, where a heavily marketed botanical turns out to sit near the bottom of the ingredient list at a fraction of a percent — the page says so. The honest caveats are the product, not a disclaimer. The full method, and the limits of what label data can tell anyone, are on the methodology page; who is responsible for it is on the author page; and everything we have got wrong so far is in the corrections log.