The use of exogenous melatonin in delayed sleep phase disorder: a meta-analysis.
If my problem is that I can't fall asleep until 3am rather than that I can't sleep at all, would timed melatonin actually be the right tool — and what time should I take it?
Top of the evidence hierarchy, independently funded. how we score evidence
Caveat on this rating: Nine small trials totalling 317 people, published in 2010, and the benefit is a shift of roughly 40 minutes to an hour in when sleep starts — real, but modest, and it delivers no extra total sleep. Effect depends heavily on taking the dose at the right time relative to one's own melatonin onset; taken at the wrong hour it can push the clock the wrong way.
In the United States melatonin is sold over the counter as a dietary supplement under the Dietary Supplement Health and Education Act of 1994 (DSHEA).
Pooling 5 randomized trials in 91 adults and 4 in 226 children with delayed sleep phase disorder, melatonin advanced the body's own melatonin onset by 1.18 hours (95% CI 0.89-1.48), moved clock-time of falling asleep 0.67 hours earlier (95% CI 0.45-0.89), and cut sleep-onset latency by 23.27 minutes (95% CI 4.83-41.72). Wake-up time and total sleep time did not change significantly. This is melatonin's real job: it shifts the timing of the body clock in people whose clock is late. It does not make you sleep more.
Worth asking
If my problem is that I can't fall asleep until 3am rather than that I can't sleep at all, would timed melatonin actually be the right tool — and what time should I take it?
Source
The use of exogenous melatonin in delayed sleep phase disorder: a meta-analysis. — van Geijlswijk IM, Korzilius HP, Smits MG. (2010)
Reputable peer-reviewed journal
Read the source: https://doi.org/10.1093/sleep/33.12.1605
DOI: 10.1093/sleep/33.12.1605
How this was scored
- Study design
- Meta-analysis of randomised trials
- Funding
- No external funding
- Published in
- Reputable peer-reviewed journal
- Sample size
- 317
- Preregistered
- No
- Conflicts disclosed
- Yes
- Independent of proponent
- Yes
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published August 19, 2026.
Where we put this study in context
Questions
How strong is the evidence behind this?
Resolv rates this source "gold standard". Top of the evidence hierarchy, independently funded. It scores 87 out of 100 on our published rubric. One caveat travels with that badge: Nine small trials totalling 317 people, published in 2010, and the benefit is a shift of roughly 40 minutes to an hour in when sleep starts — real, but modest, and it delivers no extra total sleep. Effect depends heavily on taking the dose at the right time relative to one's own melatonin onset; taken at the wrong hour it can push the clock the wrong way. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
The use of exogenous melatonin in delayed sleep phase disorder: a meta-analysis. — van Geijlswijk IM, Korzilius HP, Smits MG. (2010). Published in: Reputable peer-reviewed journal. DOI: 10.1093/sleep/33.12.1605. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Meta-analysis of randomised trials. Funding: No external funding. The researchers were independent of whoever benefits from the result. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is melatonin, circadin, slenyto, n-acetyl-5-methoxytryptamine, melatonin gummies FDA approved for this use?
No. Its current status is: Not FDA-evaluated for this use. In the United States melatonin is sold over the counter as a dietary supplement under the Dietary Supplement Health and Education Act of 1994 (DSHEA).
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.