Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid. 

While it can be used to treat focal areas, it is often best to apply this agent to the whole face and apply a heavier amount over the darkest regions. This helps prevent a blotchy complexion.

If you're facing any severe adverse effects like itching and other irritation then avoid using it and consult with your doctor. If you're not facing any of the side effects continue using it then you're safe to use it. Take a small amount of the product and apply it across the entire area of the skin.

Hydroquinone is used to lighten the dark patches of skin (also called hyperpigmentation, melasma, "liver spots," "age spots," freckles) caused by pregnancy, birth control pills, hormone medicine, or injury to the skin. This medicine works by blocking the process in the skin that leads to discoloration.

HYDROQUINONE AR