Hydroquinone
INCI: Hydroquinone · CAS: 123-31-9
Gold-standard prescription skin brightener. Very effective for hyperpigmentation but restricted in many markets for OTC use.
ComedogenicDescribes any ingredient, cosmetic, or skincare product that tends to clog pores. Scored 0 (non-comedogenic) to 5 (highly likely to clog pores).
-
IrritancyRefers to the state or quality of being irritating, provoking annoyance, or causing physical discomfort. Scored 0 (well tolerated) to 5 (likely to irritate sensitive skin).
3 / 5
EWGThe Environmental Working Group operates the EWG Skin Deep® Cosmetics Database, which evaluates the safety of tens of thousands of personal care products. Scored 0–10 based on hazard level: 0–2 low hazard, 3–6 moderate, 7–10 high.
9 / 10
Functions
active, brightening
Functions in a formula
- active
- brightening
Possible concerns
This page is continuously reviewed. Last updated 7/1/2026.
Informational only - not medical advice. See methodology.