Hydroquinone
- Effective dose
- 2–4 %
- Evidence
- 4/5· Strong
Last updated June 1, 2026
What it is
Hydroquinone is a skin-lightening agent that inhibits tyrosinase, the enzyme needed to produce melanin, thereby fading dark spots and melasma. It is long regarded as the most effective topical depigmenting ingredient. It is typically used at 2% (formerly over-the-counter) or 4% (prescription).
Benefits
Lightens hyperpigmentation and melasma; 2% and 4% concentrations are the standard effective doses, with 4% often used in prescription combination creams for more stubborn pigmentation.
When to take it
Applied PM to affected areas in defined courses rather than indefinitely; daily broad-spectrum sunscreen is essential, since UV exposure worsens pigmentation and raises ochronosis risk. Use only as directed by a clinician.
Side effects
REGULATORY AND SAFETY SENSITIVE: prolonged or high-concentration use can cause exogenous ochronosis, a blue-black skin discoloration that is difficult to reverse, and it commonly causes irritation. In the US the 2020 CARES Act removed over-the-counter monograph status, so hydroquinone is now obtained by prescription and used under medical supervision (and it is banned in the EU, Australia, and Japan); strict sun protection and limited treatment courses are advised.
Sources
Products containing Hydroquinone
No products in our database contain this ingredient yet.