Melatonin

What it does

Melatonin is a hormone the brain releases at night to signal darkness to the body. Supplements shift timing more than they sedate, which is why they work best for jet lag and delayed sleep phase.

What the research says

• Reduces jet lag symptoms

  Evidence: strong. Well replicated for eastward travel across time zones.

• May modestly reduce time to fall asleep

  Evidence: moderate. Effect is real but small in primary insomnia; lower doses often work as well as high.

DRAFT: strong for jet lag, modest for general insomnia; most store doses are 10x what the evidence supports.

What the experts say

Every position links to its source. We include skeptics alongside supporters.

• Matthew Walker

  “High doses of melatonin will block the ability of your hippocampus to form new synapses”

  Source, 2023-02-10 Cautions against melatonin: a meta-analysis shows it shortens sleep onset by only about 4 minutes and improves efficiency by about 2%, since it governs sleep timing rather than generating sleep; he warns high doses may suppress puberty and block hippocampal synapse formation needed for learning.

• Andrew Huberman

  “I personally do not recommend supplementing melatonin”

  Source Personally does not recommend melatonin supplements, noting the typical 1-3mg+ doses are orders of magnitude above natural levels and warning about negative effects on the reproductive axis and hormones.

• Bryan Johnson

  Source Takes a low 300 mcg dose of melatonin before bed, citing a clinical study showing improved sleep onset and sleep quality at that dose without next-day hangover effects.

Is it worth it?

DRAFT: extremely cheap; the main cost is using too much of it.