Melatonin is a hormone produced during the dark phase of the day by the pineal gland, a small endocrine gland in the brain that regulates the sleep-wake cycle (ie: Circadian rhythm).It also is observed in high numbers in the gut where its local effects are involved in a myriad of actions, including metabolism, immune function, gut function, inflammation, mitochondrial function, free radical scavenging, and direct anti-oxidant activity.
All these melatonin functions interact thereby balancing circadian rhythms, which can help ensure proper sleep patters, decrease oxidative stress and limit increases in reactive oxygen and nitrogen species.