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Characteristics, uses and functions of melatonin
What is melatonin?
Melatonin (N-acetyl-5-methoxytryptamine) is a hormone produced mainly by the pineal gland found in the brain. It is also produced in the retina, in the intestine and in other body tissues.
It was discovered in 1958 by Aaron Lerner. The word melatonin comes from the Greek “melas” = black and from (sero) tonina, and refers to the change of color that amphibians experience due to the influence of this hormone.
Melatonin is not only exclusive to humans, but also occurs in other animals (mammals, birds, reptiles and amphibians) and algae.
Melatonin is formed from serotonin
How is melatonin produced
The production of melatonin by the pineal gland is related to the exposure of the eyes to light. It increases when it has gotten dark and reaches the highest levels in the early hours of the morning.
During the day, it can hardly be detected. The lack of light is captured by the eyes that send their signal to the brain to stimulate the production of this hormone. The presence of light inhibits its production. For this reason it is known as “hormone of darkness”.
The production of melatonin is also conditioned by other personal factors, such as age or stress. Thus, in men, it begins to diminish after puberty and can practically disappear with old age. The production of this hormone begins after 3 or 4 months, reaching its maximum level in the prepubertal period (8 to 10 years).
From here, it goes down, so that at age 70 it is estimated that we only have 10% of the maximum level we had before puberty.
Melatonin and stress
Stress interferes with the production of serotonin and also seems to interfere with the proper 
functioning of the pineal gland that produces melatonin. According to the latest studies, folic acid deficiency can decrease the content of melatonin in the body.
Other external factors, such as the presence of more or less light depending on the season or temperature, condition the production of melatonin.
Functions of melatonin
The main functions of melatonin are the following:
- Regulate sleep: Melatonin is a hormone that regulates sleepwake cycles (which are known as circadian cycles). Melatonin, among other functions, makes us sleep or stay awake. The levels of this hormone are higher in those hours when the human body feels the need to sleep, while they are lower during the day when we must stay awake.
- Encourage the immune system: It is believed that melatonin can promote protection against infections by being able to stimulate the immune system and increase immunity.
- Act as an antioxidant: Melatonin can be considered a powerful antioxidant capable of protecting our cells against the action of free radicals. Low levels of melatonin can be related with:
- Cancer: It has been proven how the removal of the pineal gland is related to a higher rate of cancers and other anomalies produced by the degenerative influence of free radicals on the cells of the human organism, such as:
- Diseases of the circulatory system, such as increased presence of heart diseases
- Eye diseases, such as cataracts or night blindness
- Diseases of the nervous system, such as Alzheimer’s or Parkinson’s
- Metabolic diseases such as the acceleration of aging.
- Stimulate the production of hormones: Melatonin participates in the stimulation of hormones as important as growth hormone.
- Regulate reproduction: Although the regulation of reproductive cycles occurs primarily in animals, a certain relationship can be observed with respect to the human species. It has been proven that melatonin intervenes in the sexual maturation of men and women.
Puberty can be delayed with the presence of a lower amount of melatonin in the blood, while it can be delayed when the amount is high. Similarly it has been found that in southern countries, where there are more hours of light in winter, it has been observed during this time a decline in pregnancies.
Melatonin achieves these functions by inhibiting the gonadotropic hormones which influence the activity of the ovaries and testes
What is the use of melatonin?
The therapeutic use of melatonin is very broad. It has been used in the form of supplements for the treatment of numerous anomalies such as insomnia, treatment of jet lag, prolongation of youth, treatment of cancer, migraine, etc
More information on melatonin.
