Melatonin is a hormone that is naturally produced by the body and helps regulate sleep and wake cycles. It is often referred to as the "sleep hormone." Melatonin levels in the body typically start to rise in the evening as it gets darker, signaling to the body that it is time to start feeling sleepy. The production and release of melatonin are influenced by light exposure and can be disrupted by exposure to artificial light, especially from electronic devices.
When taken as a supplement, melatonin works by supplementing the body's natural melatonin levels and helping to promote sleep. It can also be used to help reset the body's internal clock for people with jet lag or shift work sleep disorder. The exact mechanisms by which melatonin works are not fully understood, but it is thought to interact with receptors in the brain that are involved in regulating sleep and wakefulness.