Why experts are cautious about using melatonin as a nightly habit
Matt Walker and Andrew Huberman both raise concerns about relying on melatonin, pointing out issues with dosing and questioning whether it is the right tool for most sleep problems. Readers reaching for a supplement habit should first understand these cautions and the behavioral alternatives.
What does melatonin actually do? Show answer
It is the body clock's signal that night has come. It helps with the timing of sleep, not with generating sleep.
What analogy does Matt Walker use for melatonin? Show answer
The starting official at an Olympic 100-meter race, who calls the runners to the line but does not run the race.
How much extra sleep did melatonin give healthy, non-elderly adults in the meta-analysis Walker cites? Show answer
Only 3.9 minutes of total sleep, with sleep efficiency improved by 2.2%.
What doses of melatonin worked in studies, and how do store products compare? Show answer
Studies used 0.1 to 0.3 milligrams. Store products commonly contain 5, 10 or more milligrams, far above the body's own levels.
Why can't the label on a melatonin bottle be trusted? Show answer
Tested products contained far less or far more than stated. Walker cites a study of more than 20 brands ranging from 83% less to 478% more.
What is Huberman's objection about staying asleep? Show answer
He says melatonin helps people fall asleep but not stay asleep, and that many wake three to five hours later unable to fall back asleep.
Why does Huberman treat melatonin as a hormonal concern? Show answer
It inhibits gonadotropin-releasing hormone and, through it, luteinizing hormone, testosterone and estrogen.
Why is caution greatest for children? Show answer
In children melatonin suppresses the onset of puberty, and the high supplemental doses they may be getting have never been studied.
For whom do Walker and Huberman see the most reasonable case for melatonin? Show answer
Older adults, roughly 60 to 65 and up, and in discussion with a doctor.
Why does light do the job better than a pill? Show answer
Light sets the timing of the body's own melatonin release. Morning light anchors the clock, and bright light late at night shifts it and makes sleep harder.
What does Walker say about cognitive behavioral therapy for insomnia? Show answer
It works as well as sleeping pills in the short term and better in the long term, with benefits lasting almost a decade in one study.
How does Walker suggest testing whether a sleep supplement works? Show answer
Record a month of baseline, take the supplement for a month, then stop for a month. If sleep does not worsen, it probably was not doing much.