Melatonin is a hormone that plays a part in the regulation of sleep and wake cycles. It’s made by the pineal gland, which is located within the brain.In order to make melatonin, your pineal gland must be able to sense light, which means you need time outside of darkness. Once melatonin production has been triggered in response to darkness, it starts being secreted into your blood stream
Melatonin helps regulate sleep and wake cycles because it reduces sensitivity to light; lower levels likely cause sleepiness at night and increased alertness during daylight hours. It may also help promote sleep by reducing the amount of time it takes for you to fall asleep.
Although melatonin is known as a sleep hormone, its release is not related to how tired you feel or how well-rested you are. Instead, it’s released on a more regular and predictable schedule throughout the day and night. When exposed to light during this cycle, your pineal gland stops producing melatonin
Melatonin is produced in response to darkness, which means if your eyes are exposed to light at all during the day, that can throw off your body’s natural production cycle.