Melatonin Test - The Sleep Hormone

Submitted on March 27, 2012

Melatonin, also popularly known as the hormone of sleep, is primarily secreted by the pineal gland. The hormone is synthesized in the melatonin pineal gland, which is present in the brain. Melatonin is an extremely important hormone which serves as the major modulator of the daily biorhythms of the body. The hormone is also responsible for the modulation of the annual biorhythms.

Properties of Melatonin

Melatonin has certain unique properties which make it different from the other hormones secreted in the body. The hormones have the ability to pass through any blood barriers of the body. It is melatonin that remains at the center of all the physiological functions. The hormone is responsible for all the complex interactions which occur between the mind and the body. Melatonin is also affected by the environment and therefore the complex interactions keep changing as our environment changes.

Levels of Melatonin

The rhythm of melatonin is diurnal and is synchronized by light. The secretion of the hormone is affected very strongly by the length of the day and even artificial illumination. Other factors like exercise and electromagnetic energy produced in the body also affect the rhythm of generation of melatonin. During the childhood, the levels of secretion are at their peak. However, this level decreases as the person steps into adulthood and grows older.

It is because of this change in the secretion levels that a person experiences the weakening of the immune system in old age. Since light suppresses the production of melatonin, people who sleep during the day and work during the night, experience less-than-perfect health. This is because their bodies secrete less melatonin than normal. If the body is secreting less amounts of melatonin, chronic fatigue may be experienced.

Melatonin is also a very important antioxidant which suppresses tumors in the body. When the body decreases the production of melatonin in our old age, we also become more prone to developing tumors. Since melatonin is such an important antioxidant, health organizations all over the world have declared night work as one of the most probable carcinogens.


Women who have low levels of melatonin in their body are also extremely prone to breast and cervical cancers. If you have not been sleeping well and experience mental fogginess during the day, the doctor will recommend you to take a melatonin test. The test may also be taken on a regular basis if you have been diagnosed with a melatonin deficiency and are being given melatonin supplements. Testing melatonin levels are critical to diagnose the problems of the endocrine system. It is also critical to measure melatonin levels for those who experience sleep disorders.