Hydroquinone is a medication used to lighten skin. It decreases the production of melanin, which changes the colour of the skin. Uneven melanin presents as freckles, dark areas of skin and age spots.
By decreasing melanin production hydroquinone decreases the concentration of melanin in the skin thereby lightening it.
Hydroquinone has been the most well known skin lightening agent for decades and while it is not the only one it is still probably the most frequently used. Hydroquinone is a safe medication when used under the guidance of a properly trained GP.