Clinically tested sounds decisive on a skin-care box. By itself, however, it leaves several questions unanswered: what was tested, how the result was measured, and whether the evidence relates to the product in your hand.
In the United States, the FDA explains that cosmetic labelling claims do not generally receive premarket approval. The rules also distinguish cosmetic claims from claims that make a product a drug. A phrase on a package should not be read as an FDA endorsement of its effectiveness.
Ask for the outcome behind the phrase
Was the study about tolerability, appearance, moisturisation or another outcome? A product being tested is different from a product demonstrating a particular benefit. Likewise, a test of an individual ingredient is not automatically a test of the finished formulation.
Look for a description of the participants, duration and comparison. A consumer questionnaire and an instrument measurement answer different questions. Neither should be silently presented as the other.
Use the claim to form questions
You might ask the company where the study summary can be read and whether the tested product matches the current formula. If only a percentage is supplied, ask what the percentage measures and how many people it represents. Avoid filling missing details with assumptions.
Keep your own needs separate from the marketing promise. A study in one population does not establish that the product will suit your skin, and a cosmetic product is not a substitute for assessment of a persistent skin problem.
If you are considering a product alongside treatment or after a procedure, discuss suitability with the relevant clinician. For ordinary shopping, the useful habit is to translate a broad claim into a specific question. Evidence becomes easier to judge when the promised outcome is stated clearly enough to examine.