Hydroquinone is an aromatic chemical compound, a metabolite of benzene.

What it is used for and where

Cosmetics

Antioxidant agent. Ingredient that counteracts oxidative stress and prevents cell damage. Free radicals, pathological inflammatory processes, reactive nitrogen species and reactive oxygen species are responsible for the ageing process and many diseases caused by oxidation.

Bleaching agent. This ingredient exerts a depigmentation and/or lightening action on the set of pigments produced by melanocytes and known as melanin, the substance responsible for skin colouration.

Fragrance. It plays a decisive and important role in the formulation of cosmetic products as it provides the possibility of enhancing, masking or adding fragrance to the final product, increasing its marketability.  The consumer always expects to find a pleasant or distinctive scent in a cosmetic product.

Hair dyeing. It is an ingredient that adds a colouring to the hair that can be temporary, semi-permanent or permanent depending on what other ingredients are added to achieve the result. The pH for hair dyeing is generally between 9 and 10.

Reducing agent. Ingredient that facilitates permanent hair waving by adjusting the pH to an optimal level.

Safety

It is a toxic agent and can promote the growth of cancer cells.

Enguita, F. J., & Leitão, A. L. (2013). Hydroquinone: environmental pollution, toxicity, and microbial answers. BioMed research international, 2013.

Chemical name    benzene-1,4-diol

CAS: 123-31-9

EC number 204-617-8

Molecular Formula  C₆H₆O₂ or C₆H₄(OH)₂