Having dark circles under the eyes is caused by genetic factors, poor blood flow and pigmentation. 1. Hereditary factors: Some people may have hereditary dark circles under the eyes, due to the congenital skin around the eyes is particularly thin, so it is more likely to form dark circles under the eyes than others. 2. Poor blood flow: If a person is in a state of long-term insomnia or less sleep, the blood vessels continue to contract, the blood circulation is not smooth, resulting in stagnation, the venous blood vessels under the eyes are abundant, but the lumen is thin, mostly capillaries, the blood is easy to stop gathering under the eyelids, the color is darker, resulting in dark circles under the eyes. 3. Pigmentation: If long-term exposure to sunlight, it will lead to skin melanin deposition and the appearance of dark circles. The appearance of dark circles is related to life habits such as staying up late and over-exerting the eyes, so patients should pay attention to adjusting their lifestyles, improving their skin condition, and paying attention to sunscreen when going out.