The hormone that regulates the sleeping cycle is called melatonin. Melatonin is produced by the pineal gland in the brain and plays a key role in regulating the body's sleep-wake cycle. Levels of melatonin typically rise in the evening as it gets dark, signaling to the body that it is time to sleep. Conversely, in the morning when it starts to get light, melatonin levels decrease, signaling that it is time to wake up. Disruptions in the production of melatonin can lead to sleep disturbances and disorders.
