Dry shampoo is a product that cleans and refreshes hair without using water. It typically contains powdered ingredients, such as starch or clay, which absorb oil and grease from the scalp and hair follicles. The dry shampoo is applied to the roots of the hair, where it absorbs excess oils and leaves behind a clean scent. It can be used to extend the time between washes, add volume or texture to the hair, or simply refresh the appearance in-between cleansings.