What is the role of melatonin in the human body?

Melatonin plays a critical role in regulating circadian rhythms and sleep patterns. It is a hormone produced by the pineal gland in response to darkness and is essential for the body’s internal clock. This regulation helps signal to the body when it is time to sleep and when it is time to wake up. Melatonin levels typically rise in the evening as light diminishes, promoting the onset of sleep, and decrease in the early morning as light increases. By influencing these patterns, melatonin helps synchronize various physiological processes to the day-night cycle, thereby contributing to overall health and well-being.

In contrast, other options relate to functions that melatonin does not primarily address. For example, metabolism regulation, immune response stimulation, and blood sugar level regulation are associated with other hormones and bodily processes rather than the primary function of melatonin.