Melatonin is a hormone that your body produces naturally. Melatonin is a hormone in your body that regulates sleep. Melatonin generation and release in the brain are time-dependent, increasing in the dark and decreasing in the light. It aids in the regulation of your sleeping habits. Melatonin generation decreases as we age. Melatonin is also available as a supplement, usually in the form of an oral pill or capsule. For short-term sleep issues, you can take a generic form of melatonin. It helps you fall asleep faster and wake up less often at night. Melatonin is often used to treat sleep problems such as insomnia and jet lag.