Melatonin is often reduced to its nickname, the "sleep hormone," but its role is more precise than that. It doesn't actually induce sleep; rather, it signals to the brain that night has fallen and it's time to prepare for sleep. Understanding how it works allows you to better utilize natural strategies to improve your sleep.
What is melatonin?
Melatonin is a natural hormone produced primarily by the pineal gland, a small structure located deep within the brain. Its secretion follows a precise circadian rhythm: almost nonexistent during the day, it begins to increase with the decrease in light at the end of the day, reaches its peak between 2 a.m. and 4 a.m., then gradually decreases until waking.
It is this variation in concentration that synchronizes the biological clock with the day-night cycle. Without a sufficient level of melatonin at the right time, falling asleep is delayed and sleep quality deteriorates. Conversely, exposure to light in the evening, particularly the blue light from screens, inhibits its secretion and delays sleep onset by 30 to 60 minutes, according to studies published in the Journal of Clinical Endocrinology .
The role of melatonin in sleep
Melatonin primarily affects two aspects of sleep: the time it takes to fall asleep and the synchronization of the circadian rhythm. Unlike sleeping pills, it does not directly prolong the total duration of sleep or increase the depth of slow-wave sleep. Its action is more subtle: it resets the biological clock so that sleep occurs at the right time.
This is why it is particularly effective in situations involving circadian rhythm disruption: jet lag after a long journey, night work, delayed sleep phase syndrome (people who cannot fall asleep before 1 or 2 a.m.). It is also useful for facilitating rapid sleep onset in people suffering from mild insomnia related to a disruption of their biological clock.
Natural melatonin and synthetic melatonin
When natural melatonin production is insufficient, synthetic melatonin supplements can be used. These are manufactured in laboratories and have a structure identical to the melatonin produced by the body. They are available in various forms: tablets, capsules, sublingual sprays, or chewable gum.
The effective dose is generally low: 0.5 to 1 mg is sufficient in most cases. Higher doses (2 to 5 mg) do not produce a proportional effect and can disrupt the natural secretion rhythm in the long term. Melatonin should be taken 30 to 60 minutes before bedtime, preferably in a dimly lit room to avoid interfering with its action.
It is generally well tolerated and does not cause physical dependence. However, prolonged use at high doses should be discussed with a doctor, particularly in children, pregnant women, and people taking anticoagulant or immunosuppressant medication.
Melatonin and plants: a common combination
In dietary supplements, melatonin is often combined with plants that have sedative properties to enhance its effect. Among the best-documented combinations are passionflower, linden, poppy, and valerian. These plants work to relax the nervous system and reduce pre-sleep anxiety, thus facilitating melatonin's effect on falling asleep. Our selection of the best plants for sleep details their properties.
Vitamin B6 is also often included in these formulas: it participates in the synthesis of serotonin, a precursor of melatonin, and has a health claim validated by the EFSA for the normal functioning of the nervous system.
Did you know that?
Flight attendants, including pilots and stewardesses, have long used melatonin to manage jet lag. Several clinical studies conducted on these professionals have helped to document the effectiveness of melatonin in rapidly resynchronizing the biological clock after a time zone change.
Frequently asked questions about melatonin
Is melatonin a sleeping pill?
No. Melatonin is not a sleeping pill in the pharmacological sense of the term. It does not sedate the nervous system like benzodiazepines. Its action is chronobiological: it resets the internal clock to facilitate falling asleep at the right time. It has no noticeable effect on the duration or depth of sleep.
What dose of melatonin should I take?
A dose of 0.5 to 1 mg taken 30 to 60 minutes before bedtime is usually sufficient for most adults. Higher doses are no more effective and may disrupt the natural secretion rhythm. It is advisable to start with the lowest dose and increase it if necessary.
Can melatonin be taken every night?
For occasional use (jet lag, temporary insomnia), melatonin is fine. For prolonged daily use, it's best to consult a doctor. The long-term goal is to correct sleep habits rather than relying on a supplement. Our tips for sleeping well detail sustainable ways to improve sleep without systematically resorting to supplements.
Is melatonin suitable for children?
The use of melatonin in children must be supervised by a pediatrician. Studies suggest it may be helpful in certain developmental disorders (autism, ADHD), but long-term data remains limited. It should not be used as self-medication by those under 18 years of age.