The causes of dark skin are as follows: 1, genetic factors: genetic genes are the most common factors leading to dark skin, the father’s skin color directly determines the skin color of the offspring; 2, sun exposure: ultraviolet light can stimulate melanin in the skin, resulting in darkening, wrinkling and aging; 3, certain diseases: such as liver disease, the body can not be metabolized properly when the toxins, resulting in dark and dark skin; 4, lack of vitamins: the lack of vitamins, will lead to aging cells can not be shed in time, pigmentation; 5, dry skin: excessive dehydration of the skin, dry skin, the appearance of the skin looks dark and rough. Usually pay attention to regular work and rest time, do not stay up late, do not smoke and drink less, eat a light diet, eat more vegetables and fruits, drink more water, go out and pay attention to sun protection.