Depigmentation caused by application of the active brightening material, rhododendrol, is related to tyrosinase activity at a certain threshold

•We investigate the causes of unexpected depigmentation induced by rhododendrol.•Melanocyte damage is related to tyrosinase activity at a certain threshold.•Melanocytes with higher tyrosinase activity produce a toxic hydroxyl-rhododendrol.•Suppression of tyrosinase activity rescues melanocytes treated with rhododendrol.