Under eye darkening, also known as dark circles or periorbital hyperpigmentation, refers to the appearance of darkened skin under the eyes. This condition can make the area under the eyes appear darker than the surrounding skin, leading to a tired or aged appearance. Under eye darkening can be caused by a variety of factors, including genetics, aging, thinning skin, allergies, dehydration, lack of sleep, stress, and certain medical conditions. It can affect people of all ages and skin types. Treatment options may include lifestyle changes, skincare products, topical creams, cosmetic procedures, or addressing underlying medical conditions.