Hydroquinone is a topical ingredient popular for skin lightening.

It’s classified as an over-the-counter drug in the United States and has been used in concentrations up to 2% within products designed to lighten skin.

While it is popular, there are many concerns regarding its safety. It is estimated that one-third of the population is allergic to Hydroquinone, and skin may become photosensitized with prolonged use, causing an actual darkening of skin.

Throughout the years, many highly respected administration agencies have recognized Hydroquinone as a potent cytotoxic (substances toxic to cells) agent with potential cancer-causing, DNA-altering properties.