Full Moon and Sleep: What Studies Show About the Moon's Influence on Your Night's Rest

In 2008 the chronobiologists Foster and Roenneberg summarised in Current Biology how the day, the seasons and the moon relate to human biology.

Their conclusion: the lunar cycle has shaped human culture, but solid evidence that the moon steers our biology was lacking.

For you that means: until a few years ago, sleep research regarded the full moon mainly as a topic for folklore.

In 2013 Cajochen and colleagues from the Centre for Chronobiology at the Psychiatric Hospital of the University of Basel retrospectively analysed sleep data from tightly controlled laboratory studies according to the phase of the moon.

Around the full moon, EEG delta activity in deep sleep was 30 percent lower, falling asleep took 5 minutes longer, sleep was 20 minutes shorter, and the body's own melatonin levels were lower.

For you that means: for the first time it looked as if a lunar rhythm could influence sleep, and without any moonlight in the room.

In 2014 Smith and colleagues from the University of Gothenburg used the same principle to examine the laboratory nights of 47 healthy young adults.

Around the full moon, sleep was 25 minutes shorter and the sleeping brain reacted more strongly to stimuli from the environment, while around the new moon REM sleep set in 30 minutes later.

For you that means: a second laboratory saw a similar trend but a different pattern in the details, and the authors explicitly pointed to individual sensitivity.

In 2014 Turányi and colleagues from Semmelweis University in Budapest analysed one polysomnography night each from 319 people who had been referred for a sleep assessment.

On full moon nights, median sleep efficiency was 74 instead of 82 percent, the proportion of deep sleep was 6 instead of 9 to 11 percent, and REM sleep began after 137 minutes instead of around 98.

For you that means: a full moon pattern also appeared in a clinical sample, although only 47 of the nights came from the full moon phase.

Back in 2006, Röösli and colleagues from the University of Bern had analysed the sleep diaries of 31 volunteers over six weeks that included two full moons.

Reported sleep duration was 6 hours 41 minutes at full moon and 7 hours at new moon, and in the morning the participants felt more tired at full moon.

For you that means: subjective experience also matched the folk belief, but the study was originally designed for an entirely different question.

In 2014 Cordi and colleagues from Zurich, Basel, Berlin and Munich rechecked the Basel findings using sleep EEG data from three large samples.

They could not confirm the results and also came across further null findings, most of them unpublished.

For you that means: striking lunar findings may have been more likely to be published than unremarkable ones, something researchers call the file drawer problem.

In 2015 Haba-Rubio and colleagues from Lausanne University Hospital examined 2,125 adults in a population-based cohort with full polysomnography at home.

Measured sleep duration was 398 minutes at full moon, 402 minutes during the waxing and waning moon and 403 minutes at new moon, with no statistically meaningful difference, and sleep structure, EEG and cortisol did not differ either.

For you that means: a large everyday sample showed no relevant lunar effect, and the title of the study advises against blaming the moon for bad sleep.

Smith and colleagues from Helmholtz Zentrum München followed 1,411 adolescents aged 14 to 17 with motion sensors and sleep diaries over a total of 8,832 days.

The moon phase was linked neither with time in bed nor with perceived sleep quality, and the trends that were found changed direction at random.

For you that means: in a large German sample, the pattern looked more like chance than like the moon.

In 2016 Chaput and colleagues analysed data from 5,812 children aged 9 to 11 from twelve countries, measured with motion sensors around the clock.

At full moon the children slept on average about 5 minutes less than at new moon, which corresponds to around 1 percent of sleep duration.

For you that means: even when an effect is measurable, it can be so small that the authors themselves doubt its significance in everyday life.

In 2021 Casiraghi and colleagues from the University of Washington measured the sleep of 98 members of Indigenous Toba/Qom communities in Argentina, some with and some without electricity, and of 464 students in Seattle.

Sleep began later and was shorter in the nights before the full moon, most clearly among the Toba/Qom three to five days before the full moon, and the effects were larger the less electric light was available.

For you that means: moonlight in the hours after dusk might have kept people awake in earlier times, and artificial light might imitate this ancient effect today.

Benedict and colleagues from Uppsala University analysed one polysomnography night each from 852 adults aged 22 to 81.

In the waxing phase of the moon, participants slept less than in the waning phase, and in this phase men also had lower sleep efficiency and more time awake after falling asleep.

For you that means: the pattern fits the moonlight idea, but the authors themselves stress that no cause can be inferred from these cross-sectional data.

In 2020 van Hasselt and colleagues from Groningen and Seewiesen used miniature EEG recorders to record the sleep of starlings in a large outdoor aviary, under natural light and natural temperature.

On full moon nights, the birds got around two hours less NREM sleep.

For you that means: under the open sky, moonlight can markedly change the sleep of animals, while in a darkened bedroom the starting point is quite different.

In 2019 Phillips and colleagues from Monash University in Melbourne exposed a total of 55 young adults to different light intensities between 10 and 2,000 lux for five hours in the evening.

On the group average, just under 25 lux was enough to suppress melatonin production by half, while for the most sensitive person this threshold was 6 lux and for the least sensitive 350 lux.

For you that means: in biological terms, the same night can be far brighter for one person than for another.

In 2011 Gooley and colleagues from Boston compared the melatonin profiles of 116 healthy adults aged 18 to 30 under room light below 200 lux and under dim light below 3 lux during the eight hours before bedtime.

Room light delayed the rise in melatonin in 99 percent of participants and shortened the nightly melatonin phase by about 90 minutes.

For you that means: the ordinary living room lamp is a louder signal for your body clock than you probably think.

In 2016 Cho and colleagues from Korea University in Seoul had healthy young men sleep one night in the dark and another night under dim light of 5 or 10 lux.

The dim light went along with more time awake after falling asleep, more light sleep and more REM sleep.

For you that means: even a light source you barely notice can shift the architecture of your sleep.

In 2016 Ohayon and Milesi linked satellite data on outdoor lighting at night with the reports of 19,136 adults in the United States.

People living in brighter areas went to bed later, slept less, were sleepier during the day and were less satisfied with their own sleep.

For you that means: the streetlight outside your window shines every night, the full moon only on a few.

In 2026, of all people, it was Cajochen, whose Basel laboratory analysis had sparked the debate in 2013, who asked 1,815 people online what disturbs their sleep.

At 36 percent, the moon was the most frequently named environmental factor, ahead of outdoor temperature and noise, and those who followed the phases of the moon named it considerably more often.

For you that means: complaints about the moon only peaked in the week after the full moon, which the author interprets, at least in part, as a result of expectation and attribution after the fact.

In 2014 Draganich and Erdal randomly told some of a total of 164 participants that they had had more or less REM sleep than average that night, regardless of how they had actually slept.

The assigned sleep quality predicted the results in an attention test and a verbal fluency test, whereas self-rated sleep quality did not.

For you that means: what you believe about your night can help shape your next day.

In 2018 Gavriloff and colleagues from the University of Oxford gave a total of 63 people with insomnia fake feedback on their sleep each morning via a wrist sensor.

Those who were randomly given a poor rating felt less alert and more tired in the evening than the group with a good rating, even though none of the feedback was based on the real night.

For you that means: a gloomy forecast for the night can make itself felt during the day, whether it comes from the lunar calendar or from an app.

In 2015 Della Monica and colleagues from the Surrey Sleep Research Centre at the University of Surrey analysed the laboratory nights of 205 healthy adults in windowless sleep laboratories and examined 21 sleep parameters.

Overall they found no lunar effect, but in women total sleep, stage 4 deep sleep and REM sleep were lower near the full moon, while in men REM sleep increased around the full moon.

For you that means: if there is an effect, it may not affect everyone equally, although the authors themselves speak only of limited evidence.

In bipolar disorder, the moon question is examined particularly closely: in 2018 Wehr described, in 17 people with very rapid mood changes, a synchrony between their mood cycles and the tidal cycles of the moon.

In 2022 Burgess and colleagues from the University of Michigan, by contrast, found no systematic group effect in nine people with bipolar disorder, and only two individuals repeatedly fell asleep later around the full moon.

For you that means: a lunar pattern might appear in individual people without applying to a whole group, but both studies are very small and more hypothesis than proof.

In 2022 Mason and colleagues from Northwestern University in Chicago had healthy adults sleep in the sleep laboratory under dim light below 3 lux or at 100 lux.

The bright night went along with a higher heart rate, lower heart rate variability and greater insulin resistance the next morning.

For you that means: light during sleep is not only a question of rest, it might also affect your heart and metabolism.

In 2024 Windred and colleagues from Monash University analysed more than ten million hours of movement data from 60,977 people in the UK Biobank.

People who slept more regularly had a 20 to 48 percent lower risk of death in the following years, and regularity predicted that risk better than sleep duration did.

For you that means: a reliable rhythm might count for more in your health than the odd short night, even though an observational study cannot prove a cause.