Hydroquinone, also benzene-1,4-diol, is an aromatic organic compound which is a type of phenol. Hydroquinone is commonly used as a biomarker for benzene exposure. The presence of hydroquinone in normal individuals stems mainly from direct dietary ingestion, catabolism of tyrosine and other substrates by gut bacteria, ingestion of arbutin containing foods, cigarette smoking, and the use of some over-the-counter medicines. In human medicine, hydroquinone is used as a topical application in skin whitening to reduce the color of skin. In 2006, the United States Food and Drug Administration revoked its previous approval of hydroquinone and proposed a ban on all over-the-counter preparations. The FDA stated that hydroquinone cannot be ruled out as a potential carcinogen. This conclusion was reached based on the extent of absorption in humans and the incidence of neoplasms in rats in several studies where adult rats were found to have increased rates of tumours, including thyroid follicular c
Solubility 10 to 50 mg/mL at 68 °F (NTP, 1992)
Formula
C6H6O2
Mol. Weight
110.11
CAS #
123-31-9
Form
Powder
State
Hydroquinone appears as light colored crystals or solutions. May irritate the skin, eyes and mucous membranes. Mildly toxic by ingestion or skin absorption.
See origin →
Functions
Light Stabilizer
Shields from UV damage
Traditional Use
Discovered in the 1920s, hydroquinone was developed as a synthetic depigmenting agent to treat hyperpigmentation and melasma. Adopted in skincare in the 1950s-1960s as one of the first clinically proven skin-lightening ingredients.
EU regulatory limit: 0.02%. - For professional use only - Avoid skin contact - Read directions for use carefully Source: EU Cosmetics Regulation (EC) 1223/2009, Annex III (Restricted Substances), Entry 14.