hydroquinone

American  

[hahy-droh-kwi-nohn, -druh-kwin-ohn] / ˌhaɪ droʊ kwɪˈnoʊn, -drəˈkwɪn oʊn /

noun

Chemistry.

1. a white, crystalline compound, C 6 H 6 O 2 , formed by the reduction of quinone: used chiefly in photography and to inhibit autoxidation reactions.

---

hydroquinone British  

/ ˌhaɪdrəʊˈkwɪnɒl, ˌhaɪdrəʊkwɪˈnəʊn /

noun

1. Also called: quinol.  a white crystalline soluble phenol used as a photographic developer; 1,4-dihydroxybenzene. Formula: C 6 H 4 (OH) 2

---

Etymology

Origin of hydroquinone

First recorded in 1860–65; hydro- ¹ + quinone

Example Sentences

Other sellers admitted using regulated ingredients such as kojic acid, hydroquinone and a powerful antioxidant, glutathione, which may cause rashes and other side-effects.

From BBC • Mar. 23, 2025

Hartman says safe alternatives to hydroquinone are available without a prescription for people who want to even their skin tone, rather than lighten it.

From Washington Post • Oct. 3, 2022

You can’t talk about hyperpigmentation treatments without mentioning hydroquinone — a controversial depigmenting agent that can bleach dark patches on the skin — which has been used for more than 40 years to treat hyperpigmentation.

From Washington Post • Jun. 20, 2021

Most of the smuggled cosmetics tend to be skin-lightening creams that were banned in Uganda in 2016 because they contain mercury and hydroquinone, which some studies have linked to damaging health side-effects.

From BBC • Jan. 8, 2020

If impure hydroquinone is used, a black, sticky precipitate will usually appear after the addition of the sulfuric acid to the hydroquinone solution.

From Organic Syntheses by Conant, James Bryant