First, black spots usually appear easily after the age of 25, which is acquired. The reasons for the formation of black spots are very complicated. Generally speaking, there are several reasons: 1. The use of inferior cosmetics, containing pigment preservatives, mixed with sweat, invades the inner layer of the skin and accelerates the production of black spots. 2. The human body is in a state of fatigue for a long time, the skin will be nervous and tired, the blood will be sour, the metabolism will slow down, and the skin will not get enough nutrition; The stratum corneum is dull because of lack of water. 3. During pregnancy, in order to protect the safety of the fetus in the uterus, the mother will secrete a lot of lutein, and some pregnant women may have dark spots on their faces, but generally they will gradually disappear after delivery. If you eat more fruits and vegetables, soy milk and milk containing vitamin C during pregnancy, defecate regularly every day, get enough sleep and keep a happy mood, you can also make the dark spots fade in time. 4. Excessive brain use and excessive sun exposure are the reasons for the increase of black spots. With the growth of age and the aging of the skin, excessive secretion of melanocytes will also make the skin black. Second, prevention methods: avoid long-term exposure, and apply sunscreen on your face before exposure. Taking vitamin C has a desalination effect. Choosing nutritious food, paying attention to proper exercise, keeping enough sleep and being cheerful can all play a role in preventing and reducing black spots.