Can Moon Cycles Really Affect Your Mood, Sleep, And Menstrual Cycle?

We decode the potential ways the moon can affect your health and hormones.

March 9, 2017
moon over water
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Crazy ideas about the moon are nothing new, and I'm no stranger to feeling a little loopy occasionally when the full moon is out. Legends and folklore claim that the moon can do everything from curse you with madness to bless you with babies, but I wanted to find out: is the lunar pull legitimate—or total lunacy?

I dug through the science and talked to an astrologer to try to unearth the truth about the celestial orb’s power over our sleep, our moods, and even the number of hospital visits we make. Here's what I learned about 5 common claims about the moon's effects—and how they measure up against the evidence. 

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moody woman
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It makes you moody

Astrologically speaking, the moon is the symbol for our feelings and our instinctual emotional reactions, says astrologer Amy Herring, author of Astrology of the Moon. “One could certainly make a case for the fullness of the moon, or the waxing and waning of its cycles, as a reflection of our own human hearts, and the ebb and flow of our feelings on a regular basis,” she says.

But does science back up the case for a moody moon? Despite the fact that the word “lunacy” comes from the Latin word for moon, "luna," no study substantiates a true connection between the lunar cycle and our psyche. In fact, a study published in the Australian & New Zealand Journal of Psychiatry found no link between the volatile behavior of hospitalized psychiatric patients and the phases of the moon.

Related: How Zodiac Signs Affect Your Garden  

woman can't sleep
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It makes it hard to sleep

Is the full moon keeping you up at night? Anthropologists have hypothesized that our ancient ancestors stayed awake later when the moon was at its brightest, and that this behavior could still affect our circadian rhythms today. Science agrees—sort of. A study in Current Biology found that when the moon was at its brightest, it took study participants five minutes longer to fall asleep, plus their total sleep duration was reduced by 20 minutes. They also found that their sleep quality wasn’t as deep.

A separate study of 5,812 children from five continents found that sleep duration for participants was five minutes less during full moons compared to new moons; yet German researchers found no link between lunar phases and fewer Z’s. 

red moon
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It syncs with your cycle

Women who flock together really do flow together. It turns out menstrual synchronicity works with the moon, too. Not only are the menstrual and lunar cycles similar in length, one study found that nearly 30% of women had their flow around the full moon. 

Your period is one thing, but what about procreation? A study published in the American Journal of Obstetrics & Gynecology found no correlation between deliveries or birth complications based on the lunar cycle, but a Japanese study did find a link between births and the moon’s gravitational pull, with a sharp increase in babies born when the moon was closer to the earth.  

Related: 9 Things You Absolutely Must Do To Survive Daylight Savings Time 

woman painting
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It makes you feel more creative

Folklore and astrology suggest that new moons are a time for new intentions and ideas, while the full moon is when those plans and ideas come to fruition.

“The roundness of the moon can represent being ‘pregnant’ with something and wanting to give birth to it,” says Herring. Think ideas, projects and creativity. Since creativity can’t be measured or scientifically linked to celestial orbits, this is more symbolic than scientifically proven. But if you're trying to jumpstart a creative endeavor, believing in the moon’s inspiration may be all you need.

woman with bandage
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It makes bad things happen

Do more accidents really happen during full moons? Ask doctors and nurses, and they’ll swear they get a flood of patients, but the research says there’s no correlation: A study in published in World Journal of Surgery found that despite what more that 40% of medical staff believe, there’s no direct relationship between full moons and hospital admission rates. 

On the flipside, the moon may help with healing. One study found that patients who underwent heart surgery during the full moon had shorter hospital stays and were less likely to die than patients who had the same operation during other moon phases.