Melatonin, known chemically as N-acetyl-5-methoxytryptamine, is a hormone produced in the pineal gland located in the brain. The pineal gland is an endocrine gland and is responsible for the production and distribution of melatonin in the human body.
The production of melatonin helps regulate the sleep-wake cycle and is responsible for the entrainment of the circadian rhythm in humans and animals. What this means is that it helps to generate sleep at the appropriate time, namely as a result of lower light levels.
How melatonin works
The pineal gland secretes melatonin at varying rates during the day and night. Melatonin receptors in the body receive this hormone as it is released from the pineal gland and into the bloodstream.
Levels of both light and dark are received by the retinal photosensitive ganglion cells in the eyes. These cells are different from the primary image receptors of rods and cones and make up only about 2% of the retinal ganglion.
These photosensitive receptors are then responsible for delivering information to the brain about the levels of light and darkness found in the external environment. These neural signals are then associated with the production of the specific hormone melatonin.
During darkness, melatonin is secreted in higher levels. The melatonin release signals the larger sleep-wake system and causes chemical changes in the human body as it gears up for sleep.
The release of melatonin thus triggers certain physiological changes in the human body including a lowering of body temperature, drowsiness and increased relaxation.
Melatonin and children
Melatonin levels are highest in young children and become increasingly delayed during adolescents. As adults, lower melatonin levels overall can lead to more difficulty sleeping and to a variety of sleep related disorders.
When you are given melatonin sleep aid it is often used to help with a variety of sleep issues. Melatonin supplementation provides safe, effective relief from insomnia, wakefulness, difficulty falling asleep, and jet-lag.