Use natural ingredients. When clients are battling hyperpigmentation, including age spots and melasma, it is important for them to use products with ingredients that are not going to permanently damage thier skin. Safe and effective ingredients for skin brightening include licorice, kojic acid, arbutin, and mulberry extract.
Use hydroquinone is very effective at lightening the skin; it is also classified by OHA as mutagenic and potentially cancer causing. Hydroquinone is a cytotoxic agent that causes mutations and alterations to DNA. It has even been banned at percents higher than one in the European Union.