Why Do I Have Dark Circles Under My Eyes?

5. Sunlight

Everyone knows the sun can burn and otherwise damage skin, but many are not aware that it is also a major cause of dark circles. When the body receives too much sunlight, it produces more melanin. This results in a tan on the rest of the body, but it also causes the often fairer skin under the eyes to darken. Because it is more sensitive, it tends to change its shade more quickly and easily than other parts of the body. Sunglasses and sunblock can help prevent this side effect.