Melatonin
A hormone released by the pineal gland at nightfall that tells the body it is time to sleep, a major regulator of the circadian rhythm and sleep.
Melatonin is the “hormone of the night”. Its release, triggered by darkness, rises in the evening, peaks around 2-4am, then falls on waking. It prepares the body for sleep and synchronises the internal clock.
The original angle (much more than a sleep hormone): melatonin is also a powerful antioxidant, notably in the mitochondria (where it is even produced locally). It protects cells during the night and plays a part in immune regulation and repair.
A surprising fact: melatonin is not exclusive to the brain. The gut produces significant amounts (up to 400 times more than the pineal gland in total mass!), linked to digestion and the microbiome.
The great disruptor: blue light. Evening screens and LEDs emit blue light that blocks melatonin release, tricking the brain (“it is still daytime”). The result: delayed sleep onset, poorer-quality sleep and a shifted body clock.
Dietary sources and modulation:
- Tryptophan (an amino acid, found in turkey, eggs, dairy products and banana) is the precursor of serotonin, itself the precursor of melatonin
- Some foods contain melatonin (cherries, walnuts, grapes)
- Magnesium and vitamin B6 support its synthesis
On supplements: melatonin as a supplement helps mainly with jet lag and certain rhythm disorders, at a low dose (0.5-1 mg). It is not a conventional “sleeping pill”, and prolonged or high-dose use is debated. The priority remains good light hygiene (darkness in the evening, natural light in the morning).