Ingredient A–Z
The evidence behind every active we use.
47 cosmetic ingredients, each with the peer-reviewed human studies behind it, an honest rating of how strong that evidence is, effective levels and the regulatory limits CSL regulatory specialists work to.
Guires Cosmetic Science Lab
The evidence behind every active we use
The Guires CSL ingredient A–Z covers the cosmetic actives our formulation scientists use most, each with what peer-reviewed trials show, how strong the evidence is, the levels that work and how we formulate with it, linked to the published studies.
Start your project with Guires CSLHow to read the ratings
Evidence strength, rated honestly.
Strong: several good randomised trials or meta-analyses. Good: controlled trials with consistent results. Moderate: promising but small or mixed trials. Limited: little controlled human evidence, so claims stay modest.
Studies were checked against publisher, DOI or journal records in September and October 2026. More ingredients are being added as their evidence is verified.
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Create your next product with CSL.
Our formulation chemists, testing scientists and regulatory specialists work alongside your team, from the first brief to a market-ready product. Bring a brief, a benchmark or just an idea: a scientist will reply within one working day with next steps and an indicative scope.