Melatonin Dosage and Timing: What the Evidence Shows
Melatonin is a timing signal, not a sedative, and its effect on falling asleep is modest. What the evidence says about dose, timing, safety, and when to ask a doctor.
The Melatonin Dosage Problem
Many melatonin supplements contain 3-10mg. Trials have used a wide range of doses, from under 1mg to several milligrams, and it is not clear that higher doses work better. They may cause more next-day grogginess, so a low dose is a reasonable place to start.
Why a Lower Dose Is a Reasonable Start
- Low doses (around 0.3-0.5mg) are closer to the amounts the body makes at night than the 5-10mg tablets common in stores
- Higher-dose tablets (5-10mg) give much higher blood levels than the body makes at night, but it is not clear they work better
- Receptor desensitization has been seen in animal and cell studies, but there is no good human evidence that normal over-the-counter doses cause it
- Next-day grogginess is a commonly reported side effect and a reasonable cue to try a lower dose
When Melatonin Actually Helps
- Jet lag (take at destination bedtime)
- Shift work sleep disorder
- Delayed sleep phase (night owls)
- Some older adults (natural production tends to decline with age, though trial results are mixed)
What the Evidence Does and Does Not Show
- Melatonin is a timing signal for the body clock, not a sedative. Its average effect on how quickly people fall asleep is modest: a 2013 PLOS ONE meta-analysis of 19 randomized trials found about 7 minutes.
- The best evidence is for circadian timing problems such as jet lag and delayed sleep phase. The American Academy of Sleep Medicine's 2017 insomnia guideline suggests against melatonin as a treatment for chronic insomnia (a weak recommendation).
- There is no good human evidence that normal over-the-counter doses reduce the body's own melatonin production or cause dependence. Some animal and cell studies show melatonin receptors can become less responsive with repeated exposure, but this has not been clearly shown to matter in people at normal doses. Long-term safety data in people are limited.
- Melatonin is sold as a dietary supplement rather than an approved sleep medicine, and independent testing has found that the amount in some products, including gummies, can differ from the label. Look for a third-party mark such as USP or NSF and treat the label dose as approximate.
When to Avoid Melatonin
If you are pregnant, breastfeeding, have an autoimmune condition, or take blood thinners or other regular medicines, talk to a doctor first. Melatonin can interact with some medications, including blood thinners, some diabetes medications and immunosuppressants, so ask a doctor or pharmacist before starting it, especially if you are pregnant, breastfeeding or taking other medicines. Dosing for children should be set by a pediatrician. If a child needs help sleeping, see our guide to melatonin for kids and ask a pediatrician before giving any.
- NIH National Center for Complementary and Integrative Health - melatonin fact sheet, safety and interactions.
- Sleep Foundation - overviews of melatonin and sleep.
- American Academy of Sleep Medicine - clinical guidelines on insomnia treatment.
- PubMed: Ferracioli-Oda et al., PLOS ONE 2013 - meta-analysis of melatonin for primary sleep disorders.
- Cochrane Library - systematic reviews, including melatonin for jet lag.
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Subscribe FreeFrequently Asked Questions
What does melatonin actually do?
Melatonin is a hormone produced by the pineal gland that signals darkness to the body. It acts mainly as a timing signal for the body clock rather than a sedative, and its average effect on how quickly people fall asleep is modest, on the order of minutes in research averages.
What is the correct dose of melatonin for sleep?
There is no single proven dose. Trials have used a wide range, from under 1mg to several milligrams, and the evidence on whether higher doses work better is mixed and not clear-cut. Many people start low (around 0.5-1mg), and the 5-10mg tablets common in US stores give much higher blood levels than the body makes at night. Higher doses may cause more next-day grogginess, headache or dizziness. Melatonin can interact with some medications, so ask a doctor or pharmacist before starting.
When should I take melatonin?
For trouble falling asleep, label directions usually suggest about 30-60 minutes before bed. For jet lag or a delayed body clock, studies time it differently, often earlier in the evening or at the destination bedtime, so it helps to ask a clinician to plan it. Taking melatonin at the wrong time of day can shift your body clock in the wrong direction.
Is melatonin safe to take every night?
Short-term use at low doses appears well tolerated by most adults, and long-term nightly use has limited safety data. There is no good human evidence that normal over-the-counter doses reduce the body's own melatonin production or cause dependence. Some animal and cell studies show melatonin receptors can become less responsive with repeated exposure, but this has not been clearly shown to matter in people at normal doses. The AASM 2017 insomnia guideline suggests against melatonin for chronic insomnia (a weak recommendation), and CBT-I is the first-line treatment. If you find you need melatonin most nights, talk to a doctor or sleep specialist.