The sudden growth of many black spots on the body is mostly due to melanin deposition, which can be seen in the following cases: 1. Endocrine disorders, long-term mental tension, excessive stress, late nights, lack of sleep, excessive fatigue, will slow down the metabolism, endocrine disorders, which will lead to melanin deposition, you need to change your daily routine, keep enough sleep, be cheerful, keep your mood relaxed, if necessary, you can also go to the hospital to use medicine to regulate. 2. 2, sun exposure, long-term exposure to ultraviolet rays may also appear dark spots, the usual sun protection work should be done, eat more food rich in vitamin C, vitamin C has a decolorizing effect. 3, age, with the growth of various parts of the body function has declined, cellular vitality, metabolism slowed down, melanin secretion increased, so that dark spots appear on the body, you can properly physical exercise to promote You can do physical exercise to promote metabolism.