There are few other supplements that are as consistently effective at supporting healthy, deep sleep as melatonin. In fact, Melatonin is an integral part in the body's natural sleep cycle called the circadian rhythm, which controls not only the wake and sleep cycle, but other physiological functions. Melatonin is secreted by a small gland located at the base of the brain called the pineal gland, where it is produced by a conversion from serotonin. Serotonin itself is created by the conversion from the amino acid tryptophan, which is often deficient in the diet. The primary stress hormone, cortisol also inhibits melatonin production and absorption, leading to restless sleep. Therefore, melatonin supplements are often recommended because they may help support deep, natural sleep and a consistent circadian rhythm cycle.