Toxicological aspects and health risks associated with hydroquinone in skin bleaching formula

The use of hydroquinone as a cosmetic skin-bleaching agent has been forbidden since January 2001. It is now available only on prescription. - The ban has been introduced because of medium-term effects such as white patches on the skin, particularly on the face (leukoderma with confetti-like depigmentation), and subcutaneous dark collections of pigment (exogenous ochronosis). - Long-term effects are a possibility; cancer being the most likely. Renal adenomas and leukaemia occurred in animal experiments indicating the nephrotoxicity and carcinogenic properties of the substance. - It is now known how hydroquinone and its metabolites can cause damage to DNA and inhibit apoptosis of mutated cells. The carcinogenic action of benzene is difficult to attribute to its hydroquinone metabolite. - Daily use of hydroquinone causes it to accumulate in the body as absorption into the skin is faster than excretion in the urine. - The use of hydroquinone as a skin-bleaching agent is accordingly unsafe and should be completely banned. Alternatives such as azaleic acid and thioctic acid (alpha-lipoic acid) are available.