After taking melatonin patients can fall asleep within 20-30 minutes, the duration is about 5-6 hours, some elderly people may have a slower metabolism and can sleep for about 7 hours. Some patients with severe sleep disorders may not be clinically effective after taking melatonin, because melatonin induces natural sleep in vivo sex hormone, which is secreted by the human pineal gland, and is not a sedative or sleeping pill. Melatonin mainly focuses on adjusting the sleep rhythm, which can overcome the difficulty of falling asleep in sleep disorders, and at the same time can improve the quality of sleep, and can play a significant role in reducing the number of awakenings during sleep. Patients taking melatonin orally during the period is recommended to regulate mainly, if there is a serious sleep disorder can assist other sedative, sleeping drugs.