What it is
Hydroquinone is a chemical used in skin lightening creams.
What it does
Hydroquinone is used to lighten hyperpigmentation, like melasma, dark spots, age spots and freckles. It works by inhibiting melanin production.
It is also a potent antioxidant.
Hydroquinone is available in over-the-counter products at 1% or 2% concentration; 4% or higher concentrations are available by prescription only.
Although hydroquinone was linked to cancer, there is no proof that topical application in small concentrations is carcinogenic to humans.
Hydroquinone can cause sun sensitivity and should therefore always be used with a sunscreen.
It can cause a condition called exogenous ochronosis, which makes skin becomes darker.
In addition, it can also cause mild irritation. Allergies are rare, but can occurr.
When exposed to sunlight or hair, hydroquinone oxidizes and becomes brown. Therefore, products containing this ingredient should be packaged in non-transparent containers.