The ingredient, explained

Hydroquinone

Research examined HYDROQUINONE under the stated study conditions.

Stabilising

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Ingredient guide

What it is and what it does

Hydroquinone

About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗

Stabilising: Helps maintain the stability of ingredients or the finished formula.

Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗

Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.

A closer look

What the research shows

Human topical treatment study

The 4% hydroquinone group reported greater melasma improvement than placebo, with side effects reported in that group.

What this does not tell us

30 enrolled and 25 completed across hydroquinone and separate whitening-complex groups. Three-month trial with sunscreen use, small sample and limited follow-up. Results do not establish long-term safety or unrestricted cosmetic use.

Sources for this summary. PubMed 12709008 ↗

Research review checked Oct 1, 2026

Review supplied candidate titles and available abstracts selectively for exact identity; targeted primary PubMed/publisher searches. This is not an exhaustive systematic review.