The pineal gland in the brain produces melatonin, a hormone. It is involved in the regulation of the body's circadian rhythms, which are the natural cycles that govern sleep and wakefulness.

Melatonin is primarily produced at night and is believed to play a key role in promoting sleep and regulating the body's internal clock. It is also thought to have other important functions in the body, including regulating immune function, antioxidant activity, and the release of other hormones.

Melatonin supplements are often used as a natural sleep aid and may be helpful for people who have difficulty falling or staying asleep. They are also sometimes used to alleviate symptoms of jet lag, shift work sleep disorder, and other conditions that disrupt the body's natural sleep-wake cycle.

Melatonin supplements are generally considered safe for short-term use but may have side effects such as drowsiness, headaches, and dizziness. They may also interact with certain medications, so it is important to talk to a healthcare provider before taking melatonin supplements.

In addition to supplements, there are also many natural ways to boost melatonin levels, including getting regular exposure to natural light during the day, avoiding bright lights in the evening, and maintaining a consistent sleep schedule. Lifestyle factors such as stress reduction, regular exercise, and a healthy diet may also play a role in promoting healthy melatonin levels and improving sleep quality.