Melatonin (pronounced mɛləˈtoʊnɪn), also known chemically as N-acetyl-5-methoxytryptamine, is a naturally occurring compound found in animals, plants, and microbes. In animals, circulating levels of the hormone melatonin vary in a daily cycle, thereby allowing the entrainment of the circadian rhythms of several biological functions.
Many biological effects of melatonin are produced through activation of melatonin receptors, while others are due to its role as a pervasive and powerful antioxidant, with a particular role in the protection of nuclear and mitochondrial DNA.
In mammals, melatonin is secreted into the blood by the pineal gland in the brain. Known as the “hormone of darkness”, it is secreted in darkness in both day-active (diurnal) and night-active (nocturnal) animals.
It may also be produced by a variety of peripheral cells such as bone marrow cells, lymphocytes and epithelial cells. Usually, the melatonin concentration in these cells is much higher than that found in the blood but it does not seem to be regulated by the photoperiod.
Melatonin-rich plant feed, such as rice, ingested by chicks has been shown to reach and bind to melatonin receptors in their brains. No food has been found to elevate plasma melatonin levels in humans so insomnia can’t be addressed and resolved by food but can be with melatonin supplementation.
In humans, melatonin is produced by the pineal gland, a gland about the size of a pea, located in the center of the brain but outside the blood-brain barrier. The melatonin signal forms part of the system that regulates the sleep-wake cycle by chemically causing drowsiness and lowering the body temperature, but it is the central nervous system (more specifically, the SCN) that controls the daily cycle in most components of the paracrine and endocrine systems rather than the melatonin signal (as was once postulated).
Infants’ melatonin levels become regular in about the third month after birth, with the highest levels measured between midnight and 08:00 (8 AM).
In humans, 90% of melatonin is cleared in a single passage through the liver, a small amount is excreted in urine, and a small amount is found in saliva.
Production of melatonin by the pineal gland is inhibited by light and permitted by darkness. For this reason melatonin has been called “the hormone of darkness”. Its onset each evening is called the Dim-Light Melatonin Onset (DLMO). Secretion of melatonin as well as its level in the blood, peaks in the middle of the night, and gradually falls during the second half of the night, with normal variations in timing according to an individual’s chronotype. However, insomnia can occur to people who are so tired that all they can think about is sleeping but their insomnia keeps them up when sleeping is all that they want.
It is principally blue light, around 480nm, that suppresses melatonin, increasingly with increased light intensity and length of exposure. Until recent history, humans in temperate climates were exposed to few hours of (blue) daylight in the winter; their fires gave predominantly yellow light. Wearing glasses that block blue light in the hours before bedtime may avoid melatonin loss. Kayumov et al. showed that light containing only wavelengths greater than 530 nm does not suppress melatonin in bright-light conditions. Use of blue-blocking goggles the last hours before bedtime has also been advised for people who need to adjust to an earlier bedtime, as melatonin promotes sleepiness.
Melatonin has been studied for the treatment of cancer, immune disorders, cardiovascular diseases, depression, seasonal affective disorder (SAD), circadian rhythm sleep disorders and sexual dysfunction, so if problems sleeping because of insomnia is a concern think of all the other potential health benefits melatonin suspended gel strips named REM can do for you or anyone else for that matter. Several clinical studies indicate that supplementation with melatonin is an effective preventive treatment for migraines and cluster headaches as well.
Besides its function as synchronizer of the biological clock, melatonin also exerts a powerful antioxidant activity. The discovery of melatonin as an antioxidant was made in 1993. In many less complex life forms, this is its only known purpose. Melatonin is an antioxidant that can easily cross cell membranes and the blood-brain barrier. Melatonin is a direct scavenger of OH, O2−, and NO. Unlike other antioxidants, melatonin does not undergo redox cycling, the ability of a molecule to undergo reduction and oxidation repeatedly.
For best bioavailability, melatonin comes in a gel strip so that it naturally gets to the blood stream most effectively with a low dose as with Agel’s REM. Get the rest you need with Agel’s REM, the only sleeping aid you will ever need without any inconvenience and side effects. Say hello to sleeping and goodbye to insomnia with REM!