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Melatonin: explanations from Dr Duforez, a sleep specialist

Sleep is an active process consisting of alternating, regulated and dynamic periods of awake and asleep states. The regulation mechanism involves several processes, notably the circadian process which determines the times at which we fall asleep and wake up. Melatonin plays a synchronisation role in this process, stabilising and reinforcing the circadian rhythms.


What is melatonin?

Melatonin is a substance which has been the subject of a great deal of interest since it was discovered in the 1960s. This natural hormone is secreted by the brain, particularly by the pineal gland. Melatonin synchronises the body’s rhythms, particularly the extremely important wake-sleep cycle.

What benefits does a melatonin supplementation offer?

In our modern world, we are exposed to ever-increasing light levels, particularly in recent times from screens. This is problematic since a remarkable fact about melatonin is that it is only secreted in darkness. Consequently, looking closely at screens blocks the natural secretion of melatonin and creates pathologies which may not even have existed thirty years ago. The result is that people fall asleep later and later, and then their sleep is increasingly broken up. Many people end up accumulating a sleep deficit because the times when they can sleep are incompatible with the demands of their social and professional life.
To add to the problems, many people work shifts or outside of normal working hours, often with partners in different time zones. In these particular cases, however, melatonin can alleviate the issues to a certain extent. 

How to take melatonin correctly

Melatonin can be used in two ways. The first is as a “chronobiotic”, i.e. as an agent which can adjust the phases of the body clock. Its use in this way is recommended to people who have problems falling asleep. Note that the melatonin should be taken 2 or 3 hours before going to bed, and at a relatively low dose of about 1 mg.   
The second way to use melatonin involves using a sustained-release form of the supplement. The effect induced is called the “soporific” effect of melatonin and it is effective in preventing people from waking early in the morning; a problem which affects almost 1 in every 2 French people. This effect is achieved at doses of around 2 mg.

Are there any side effects or contraindications?

There are a few adverse reactions which can occur, notably a certain drowsiness the day after taking melatonin if the dose taken was too high. Another important point to note is that the effects of melatonin are, in some cases, greater in people who are also taking anticoagulation medication (and certain other medicines). This effect is due to the fact that melatonin is metabolised by the liver. Anyone taking anticoagulants must therefore be very cautious about also taking melatonin, and always check beforehand with a healthcare professional.
In view of the fact that it is a natural and active hormone, a few precautionary principles apply: 

  • Not recommended for pregnant women
  • It should not be prescribed for long-term use. Habituation may occur, although a more likely explanation for this is that the body clock follows a three-week cycle. Because of this natural body clock cycle, melatonin treatments generally last for three weeks.

In conclusion, melatonin supplementation provides a valuable strategy for managing body clock problems, although its effects vary from person to person. Melatonin can be used in two ways: as a chronobiotic agent at relatively low doses (taken a few hours before going to bed) and as a soporific to prevent early morning wakening, a problem which affects one in every two French people.

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