Vanish contains hydroquinone, a prescription skin depigmenting agent that has been clinically proven to effectively treat skin discoloration caused by a range of conditions. While hydroquinone is a safe and effective option when prescribed by a board-certified dermatologist, it is not meant to be used for more than 6 months. If you are initially prescribed hydroquinone, you will be automatically switched to a non-hydroquinone formulation after 6 months, which contains azelaic acid (15-30%).