Monobenzone 20% is a prescription depigmenting cream used mainly for extensive vitiligo to lighten the remaining normal skin so that it matches the white patches and produces a uniform skin tone. It contains monobenzone, a derivative of hydroquinone, which works by increasing the loss of melanin from pigment cells and can lead to permanent loss of color in treated areas. It is meant for external use only and should be used strictly under dermatologist supervision, especially because the depigmentation effect is usually irreversible.