Melatonin is a health product, eat how long to stop there is no specific regulation, is generally based on the degree of their own symptoms to reduce to determine. Generally one month as a cycle, if the insomnia disappears or significantly reduced can consider stopping, need to take under the guidance of a doctor. Melatonin is mainly an amine hormone produced by the pineal gland in mammals and humans. It has a variety of physiological functions such as promoting sleep, regulating jet lag, anti-aging, regulating immunity, and anti-tumor. Supplementing melatonin from outside the body can maintain the melatonin level in the body in a young state, adjust and restore the circadian rhythm, thus deepening sleep, improving sleep quality and improving the functional state. Melatonin is a neurotransmitter of its own, long-term use will lead to a decrease in the secretion of reactive neurotransmitters, and it is easy to rebound after discontinuing its use, leading to disruption of the biological clock. Some patients may experience adverse reactions such as depression and menstrual disorders due to long-term use. Teenagers, pregnant women and lactating women should use melatonin with caution, and should seek medical diagnosis if insomnia and other conditions occur.