Discoloration Active Ingredients In Lightening Creams

4-Hydroxyanisole (4HA) (Mequinol)

Similar to HQ, 4-hydroxyanisole (4HA) is cytotoxic to melanocytes. Reports indicate it is clinically effective in inhibiting melanogenesis when used as a combination of 2% 4HA cream and 0.01% retinoic acid. The authors reported minimal local skin irritation with this combination. Two percent 4HA alone did not produce significant hypopigmentation. Mequinol is used in Europe in concentrations ranging from 5-20% and is approved in the United States for the treatment of solar lentigines.