Skin-lightening agents are cosmetic ingredients that are used to reduce the amount of melanin in the skin, leading to a lighter complexion. Melanin is a pigment that gives color to the skin, hair, and eye. It is produced by specialized cells called melanocytes. Skin-lightening agents work by inhibiting the production of melanin, reducing the transfer of melanin to the skin's surface, or removing melanin from the skin. These agents are commonly used to treat hyperpigmentation, which can be caused by sun exposure, aging, hormonal changes, or skin trauma. Common skin-lightening agents used in cosmetic products include kojic acid, arbutin, vitamin C and niacinamide. These ingredients work by blocking the activity of the enzyme tyrosinase, which is responsible for the production of melanin.