Melanin synthesis inhibitors are used to treat hyperpigmentation of the skin. These medications work by reducing the production of melanin, the pigment responsible for skin color, which helps to lighten dark patches on your skin. Melanin synthesis inhibitors are typically available in topical forms, such as creams and gels. An example includes hydroquinone (Melquin). You apply these creams directly to the affected areas to help improve your skin.