Arbutin

• Arbutin is a hydroquinone derivative found in the bearberry extract. This agent was long believed to act as a depigmenting agent.
• However, there are no human or even animal studies that confirm the efficacy of arbutin as a skin whitener. In addition, recent in vitro studies have cast doubt on its efficacy as a depigmenting agent. Some of such studies have shown the inefficacy of arbutin to produce depigmentation. Other studies have even found evidence of a pigmentation enhancing potential for arbutin when used in high concentrations !

Source of information: here