Melatonin is a hormone found in plants, animals, microbes and humans. Its chemical name is N-acetyl-5-methoxytryptamine. Melatonin is produced in the epiphysis cerebri (the pineal gland) of the brain. The pineal gland secretes melatonin into the blood usually when it is dark outside. Studies have shown that melatonin plays a role in regulating the biological sleep-wake cycle. Melatonin is also an antioxidant.
The formation and release of melatonin is cyclical, and its level is elevated at night and during the daytime diminishes. The secretion of melatonin increases once it gets dark, goes up until the middle of the sleep cycle (between 2 and 4am), then decreases as the night goes on. This is referred to as the circadian rhythm of the sleep cycle. Studies have shown that melatonin levels usually are higher in early childhood and start to decrease in adolescence. Melatonin continues to gradually lower all the way into middle age and by the time you are in your 60’s and 70’s the level of melatonin is very low. This fact may be the reason that older people often have difficulty sleeping.
Such a relationship between melatonin levels and sleep quality was the basis for the use of melatonin as a soporific. Another use for melatonin is helping travelers crossing several time zones (jet lag) and nightshift workers who violated the regime of the day. It should be noted that if using for nightshift workers who sleep during the day, the environment for sleep should mimic that of evening time. Also not all who use melatonin for sleep for this purpose has success in changing the circadian rhythm of the sleep cycle.
There is evidence that melatonin is a potent antioxidant. The ability of antioxidants to prevent the damaging of free radicals is now associated with the prolongation of life. Antioxidant properties of melatonin were ranked right up there with vitamins C and E. The medicinal properties of melatonin can be helpful with cardiovascular disease, preventing risk of cancer, Alzheimer’s and some forms of Parkinson’s disease. Most of the data is preliminary and was obtained in experiments with animals.
In most scientific publications people are encouraged to use melatonin as a dietary supplement, like a daily vitamin for short term use. In the U.S melatonin is considered a dietary supplement and sold in accordance with the recommendations provided in the Act on food additives in 1994 (Dietary Supplement Health and Education Act). The product is sold in pill and liquid form in health food stores, pharmacies, supermarkets, and can also be ordered by mail. Melatonin made synthetically is said to be safer than the melatonin that comes from the pineal gland of animals. The variety that comes from animals may have viruses or biological contaminants from the animal it came from.