HYDROQUINONE treats dark spots on the skin caused by hormones, aging, or sun exposure. It works by decreasing the amount of melanin, a pigment your body makes that gives your skin color. This reduces the appearance of dark spots. Sun prevention measures, including sunscreen, are often combined with this medication. It belongs to a group of medications called skin-lightening agents. Get Nuquin HP for as low as $38.69, save up to 80% off the average retail price for the most common version, by using a GoodRx coupon.