Podcast episode 55 (in German)
Melatonin: the darkness hormone fact-checked
August 25, 2026
Melatonin is one of the oldest molecules of life and probably the most misunderstood one on the supplement shelf. It does not send the body to sleep but sets its internal clock, and along the way it protects the cells’ power plants.
What it is about
The pineal gland releases melatonin as soon as it gets dark, thereby signaling to every cell that it is night. It does not force sleep like a sleeping pill but opens the sleep window; experts speak of a chronobiotic. The episode explains why timing is often more important than quantity, what studies actually show about its effect and where melatonin has its strengths: jet lag, shift work, night owls and the shifted rhythm in old age. Added to this are its second role as an antioxidant in the mitochondria, the safety questions and light in the evening and in the morning. At the end stands a signal that orders the rhythm instead of forcing sleep.
Key points
- At night, the body produces only about 0.1 to 0.3 milligrams of melatonin; commercially available tablets deliver 10 to 50 times this natural amount.
- The MIT researcher Richard Wurtman showed in the early 2000s that small, near-physiological amounts work as well on sleep as high ones, without the morning fog.
- Meta-analyses across dozens of randomized trials show on average about 7 to 12 minutes faster sleep onset; for jet lag, the effect has been considered well supported since the Cochrane review.
- In night owls with delayed sleep phase, melatonin acts as a phase shifter; studies show shifts of the internal clock by 1 to 2 hours within a few weeks, combined with morning light.
- The clock receptors in the eye react most sensitively to blue light at around 480 nanometers; bright screen light in the evening reduces the body’s own secretion by up to half.
- No dependence develops: no tolerance, no withdrawal, and the body’s own production does not shut down permanently; excessive amounts can cause morning grogginess and vivid dreams.
Addendum (as of October 6, 2026): In the Cochrane review on jet lag, 0.5 to 5 mg had similar effects; with 5 mg, participants fell asleep faster and slept better than with 0.5 mg, and above 5 mg there was no additional benefit. According to the German Federal Institute for Risk Assessment (BfR), the daily amounts of the products listed in Germany range from 0.1 to 3 mg; products with up to 10 mg are also offered online. The current state of knowledge is summarized on the topic page Melatonin.
Where the data stop
Melatonin is an adjusting dial, not a hammer: its effect on falling asleep is measured in minutes. Those who benefit most reliably are people with rhythm problems and older people, whose nocturnal secretion declines markedly from midlife onwards; for them, Circadin is an approved prolonged-release medicine. Its role as a cell protector, from intensive care medicine to support during cancer therapies, is predominantly a matter of research, not ready for practice. There are only small studies on melatonin from foods such as sour cherries.
Pregnant and breastfeeding women should be cautious owing to a lack of data; with autoimmune diseases, blood thinners or blood pressure medication, the question belongs in a medical consultation, and children always belong in a physician’s hands. Sleep disorders of clinical significance should be evaluated. And before any tablet comes light: dimmed evenings, bright mornings, a dark bedroom.
Listen (in German)
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Published on August 25, 2026.
The topic in the database
- The body’s own darkness signal. Works most strongly in jet lag and delayed sleep phase, in ordinary insomnia by only a few minutes.Melatonin
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Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-10-06.