Melanin is a class of dark polymers Prescription facial bleach by the body through the process of melanogenesis. Hydroquinone is a strong inhibitor of melanin production; it prevents dark skin from making the substance responsible for skin color. Thankfully this side effect is quite rare, and is usually seen with long-term use years of creams that contain this ingredient. Prescription facial bleach intake of glutathione could be harmful when combined with other skin whitening agents such as hydroquinone, which is a carcinogenic element, and monobenzonewhich causes irreversible depigmentation. Pure forms of arbutin are considered more potent for affecting skin lightening.