The Science On How Magnesium Promotes Sleepiness + Best Forms For Bed
Think of magnesium as fuel for your busy body. Without it, getting just about anywhere will be a struggle. The essential mineral helps support many physiological processes, including active ones like muscle contraction and more calming ones like relaxation and sleep.* If you're curious about magnesium's sleepy properties and how to incorporate them into bedtime, read on.
What is magnesium?
Magnesium is a mineral that fuels over 600 processes in the body. Having adequate levels of magnesium will go a long way in ensuring you have a healthy heart1, skeletal system2, and inflammatory response3, as well as steady blood pressure4, blood sugar, and energy levels5.*
It's important to take in enough magnesium from your diet, as your body doesn't produce the almighty mineral on its own. Unfortunately, data suggests that this is easier said than done. It's currently estimated that 43% of U.S. adults6 don't meet their daily magnesium needs7 (310 to 320 milligrams for women, 360 milligrams for pregnant women, and 400 to 420 milligrams for men, FYI) from food alone. Some of this gap is due to the way that our food is grown in this country, which you can read all about here.
This is where daily magnesium supplements come in handy. Depending on the form, these pair the magnesium with an organic compound (e.g., amino acid or citric acid) molecule (e.g., oxygen) to assist with delivery and ensure mineral levels are up to snuff. Some of the most common forms (i.e., complexes) of magnesium supplements include magnesium bisglycinate, magnesium citrate, and magnesium oxide. Though all of these supplements contain magnesium, they work slightly differently thanks to those secondary "helper" compounds.
What magnesium has to do with sleep.
In addition to being essential for energy production, magnesium also plays a role in sleep in a few key ways.
For starters, magnesium stimulates the activity of GABA8 receptors, which help the brain calm down from periods of excitement and return to homeostasis.* So after a long day, consuming magnesium can help you slip into "rest and recover" mode more easily.* The mineral also seems to help regulate our sleep-wake cycle, with research showing9 that the regularity of our internal clocks is influenced by our magnesium status.*
"The relaxing and calming effects of magnesium definitely help with sleep, and also help with mood,"* Ella Soderholm R.N., MNT, a registered nurse and master nutrition therapist, tells mbg.
Indeed, initial research10 confirms that people with higher magnesium levels (thanks to supplementation) tend to have less of the stress hormone cortisol.* And in one 2011 clinical trial11, those who took a nightly supplement of magnesium, melatonin, and zinc found it easier to fall asleep and wake up energized.*
Beyond just making us calm and sleepy, magnesium has also been shown to improve overall sleep quality10 and increase the amount of time we spend in slow-wave sleep, which is important for memory consolidation and muscle repair.*
All this to say, magnesium-rich foods and supplements can help us relax and feel pleasantly sleepy.* And when paired with a solid bedtime routine, they may even promote deeper, more efficient rest.
How to use magnesium for sleep.
Given the mineral's relaxing qualities, it's not a bad idea to snack on foods that are high in magnesium and low in added sugar—such as bananas, nuts, and seeds—before bed. (Just make sure that you're not eating too much too late in the evening, as that can disrupt your sleep.)
Taking a magnesium supplement close to bedtime can also help you benefit from the mineral's calming qualities.* However, you'll want to be sure to look for one with the right helper compounds. Some magnesium complexes—like magnesium malate, magnesium citrate, and magnesium oxide—tend to be less bioavailable and more energizing. This means that in addition to revving the body up, they can also get the bowels moving (which you might not want right after tucking in for the night).
Instead, magnesium bisglycinate—magnesium paired with two glycine amino acid molecules—is more easily absorbable and less likely to trigger GI side effects. The amino acid glycine has also been shown to make it easier to fall asleep and stay asleep12 and reduce daytime sleepiness13, making this supplement form a fantastic one for bedtime.*
Most experts recommend taking magnesium supplements one to two hours before bed to give them enough time to spur sleepiness and kick-start the body's relaxation response.* However, if you're taking a sleep supplement that pairs magnesium bisglycinate with other ingredients, you'll also want to take those into account when deciding on optimal timing.
Side effects and safety.
Magnesium supplements are generally considered very safe and come with few side effects. This is a natural mineral your body needs daily (and in relatively large amounts—several hundred milligrams), after all. That being said, looser stools14 (which can be a benefit for those taking magnesium to get things moving down there), upset stomach, and GI discomfort14 can occur when starting a new supplement. Taking a magnesium form that is more bioavailable and easier to absorb will minimize the likelihood of these side effects.
Everyone is different, but starting with a lower dose is generally recommended with most supplements. Going above the National Academies' tolerable upper intake level for supplemental magnesium (350 milligrams15 for adults) is not recommended for routine consumption unless otherwise instructed by a doctor.
Magnesium supplements have the potential to interfere with certain heart medications and antibiotics. For those taking thyroid hormone replacement therapy, you should space minerals like magnesium (calcium and iron) away from your thyroid pill by several hours for optimal absorption of the medicine. Always check in with your health care provider before adding any new supplement to your routine.
Magnesium can do many things for us—including making us a little sleepy. When paired with other healthy nighttime habits, consuming magnesium-rich foods and supplements (depending on the complex) before bed can help promote high-quality sleep.*
Emma Loewe is the Sustainability and Health Director at mindbodygreen and the author of Return to Nature: The New Science of How Natural Landscapes Restore Us. She is also the co-author of The Spirit Almanac: A Modern Guide To Ancient Self Care, which she wrote alongside Lindsay Kellner.
Emma received her B.A. in Environmental Science & Policy with a specialty in environmental communications from Duke University. In addition to penning over 1,000 mbg articles on topics from the water crisis in California to the rise of urban beekeeping, her work has appeared on Grist, Bloomberg News, Bustle, and Forbes. She's spoken about the intersection of self-care and sustainability on podcasts and live events alongside environmental thought leaders like Marci Zaroff, Gay Browne, and Summer Rayne Oakes.