Melatonin and the pineal gland

In short: Melatonin is a hormone released mainly at night by the pineal gland in the brain, which regulates the sleep-wake cycle. Light inhibits its production, darkness promotes it.

In more detail: The pineal gland, a small, pea-shaped organ deep in the brain, receives information about brightness from the eye’s retina via a complex neural pathway.

In detail

• Daily rhythm: Melatonin concentration in the blood rises in the evening, peaks at night, and drops again in the morning.
• Light sensitivity: Blue light from screens in particular strongly inhibits melatonin production, which can make falling asleep harder.
• Internal clock: Melatonin is closely linked to the circadian rhythm, coordinated by a brain region called the suprachiasmatic nucleus (nervensystem-aufbau-und-funktion).
• Jet lag: After crossing time zones, melatonin release needs a few days to adjust to the new light-dark rhythm.
• Seasonal variation: In winter, with shorter days, more melatonin is often produced, which contributes to stronger tiredness in some people.
• Melatonin as a supplement: Low-dose preparations are sometimes used to support sleep, but should be used with medical advice.
• Aging: Melatonin production often declines with increasing age, which is linked to sleep problems in older people (schlafzyklen-und-traumphasen).