The Research On Magnesium Supplements For Sleep & Which Ones Are Best At Bedtime*

While certainly not a cure-all, the right supplement can support high-quality sleep when paired with healthy nightly habits (read: minimizing electronics, managing stress, and keeping bedtime consistent). There are many sleep supplements on the market these days—some with more research behind them than others. Today, we're investigating the role that magnesium supplements, in particular, can play in a solid night's sleep.*

Magnesium is an essential mineral to the human body that has an important role in energy production, bone development, muscle contraction, and much more.*

"The ability of our nerves to transmit signals throughout our entire central nervous system (brain, spinal cord, etc.) is dependent on magnesium. The metabolism of carbohydrates and fats for ATP energy requires magnesium. The regulation of blood pressure and heart rate directly involves magnesium. This mineral is even required for the production of DNA, RNA, and proteins. Talk about ubiquitously important,"* explains mbg's vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN.

Our bodies cannot produce magnesium, so we must consume this essential macromineral daily through diet. This can be easier said than done, as some industrial agricultural practices strip the essential mineral out of food.

It's estimated that 43% of U.S. adults1 currently fail to meet their daily needs through diet alone. Ferira adds, "To put this magnesium deficit in further perspective, we're talking about over 100 million adults failing to achieve their nutritional requirements daily."

The magnesium in our bodies also tends to naturally dip as we age, due to reduced intestinal absorption, reduced bone storage, and excess urinary loss. This makes maintaining healthy magnesium levels a lifelong endeavor for many.

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Ever the multitasker, magnesium has its hand in many processes that affect sleep. For starters, it seems to help regulate our circadian rhythm2—the internal clock that tells the body when to be awake and when to go to bed.*

In a small 2012 study in the Journal of Research in Medical Sciences3, researchers monitored a group of 46 elderly people (age 60 to 75 years) for eight weeks. Compared to those who were given a placebo, those who took magnesium daily showed statistically significant improvements in sleep onset latency, sleep duration, and sleep efficiency (the percentage of time spent asleep while in bed).*

Darley notes this is the most significant array of improvements for sleep found in a supplemental magnesium clinical trial thus far.* Ferira points out that in addition to these obvious markers of sleep quality, those who took magnesium in this study also showed reduced levels of cortisol, the stress hormone, further supporting magnesium's relaxing potential.*

When combined with melatonin and zinc, nightly magnesium supplementation improved the sleep quality of 43 older people living in a long-term care facility in Italy in another 2011 clinical trial4.* Compared to the placebo group, those who took the supplement found it easier to fall asleep and wake up energized.*

Additionally, Ferira notes that magnesium has been shown via a 2002 EEG study to increase slow-wave sleep—the deep sleep stage that is essential for memory consolidation and muscle repair.* The same research5 found that magnesium may help regulate our HPA axis, quelling the energizing fight-or-flight stress response.*

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Beyond its potential sleep benefits, there are plenty of other reasons to supplement with magnesium daily—especially if you are not getting enough of the mineral from food alone.* Ferira shares that magnesium "promotes electrolyte balance, because it is an electrolyte, as well as muscle relaxation6."*

Ruhoy and Darley note that the mineral plays a critical role in vitamin D transport and activation in the body, plus kidney health, blood pressure balance, and more7.* "Hence, the reason I often recommend magnesium supplementation for clients," Ruhoy adds.

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All magnesium supplements pair the mineral with another compound (e.g., oxygen for the oxide form, glycine for the bisglycinate form, citric acid for the citrate form, etc.) to assist with its delivery. When it comes to the best type of magnesium supplement for sleep, Ruhoy says it's typically magnesium glycinate.*

"Magnesium glycinate is easily absorbed, does not have many GI side effects, and contains glycine,"* she explains. The amino acid glycine has sleep benefits of its own and has been shown to make it easier to fall asleep and stay asleep8 and reduce daytime sleepiness9.*

Other popular types of magnesium supplements include:

To further increase magnesium intake before bed, you can also eat foods that contain the mineral—such as bananas or dark chocolate.

No matter what form of magnesium you're taking, you'll want to stay below the NIH's tolerable upper intake level for supplemental magnesium sources, specifically, 350 milligrams10 (unless otherwise instructed by a doctor). Darley says a dose of 200 milligrams before bed will be plenty for most people.

To put these numbers in perspective, women need upward of 320 milligrams of magnesium daily11 (with even higher needs during pregnancy), while men need 420 milligrams. And as Ferira explains, "Food and supplemental sources of magnesium are not at odds; they are directly complementary and even prudent."

While you can really take a magnesium supplement at any time of the day, those who are using it for sleep will want to do so in the hours leading up to bedtime.* The exact timing depends on the person, the type of magnesium, and the exact supplement.

"If the magnesium supplement contains other sleep-supporting ingredients, then the entire arc of that formula should be considered for the timing of consumption,"* notes Ferira.

For example, we recommend taking mindbodygreen's sleep support+ formula—which pairs magnesium bisglycinate (i.e., the magnesium mineral plus two amino acid glycine molecules) with jujube extract and PharmaGABA®—30 minutes to two hours before bed. "PharmaGABA® would drive the time-to-take discussion and decision making since its clinical efficacy is shown at 30 minutes to a couple of hours before bedtime," Ferira explains.*

You'll also want to consider your own sleep needs: If falling asleep is a challenge for you, taking a supplement on the earlier side will help it kick in by the time you get into bed. If staying asleep is the issue, you could likely take it closer to your snooze.

Finally, the timing will depend on the type of magnesium you're taking. Since less absorbable forms like magnesium oxide can stimulate the bowels, you definitely won't want to take those too close to bedtime to save yourself a midnight bathroom run.

RELATED STORY: What Time Of Day Should You Take Magnesium? It Depends

Magnesium glycinate tends to be the best type of magnesium supplement to take for bed because it's gentle on the stomach and easy for the body to absorb12.*

When searching for the right magnesium glycinate supplement for nightly use, you'll want to look for something that's easy to incorporate into your routine—be it a capsule or powder to add to bedtime brews. Some magnesium supplements need to be taken with food, which is also important to note.

Be sure to look for a supplement that has a short, scannable ingredient list that is free of binders, preservatives, and artificial colors or flavors. If the supplement contains any other active ingredients beyond magnesium, those should be backed by clinical research. mbg's list of the year's best sleep supplements might be helpful as you start your search.

RELATED STORY: Which Type Of Magnesium Is The Most Absorbed By The Body?

There is no one magic bullet that ensures great sleep night after night (alas!), and consistent high-quality rest stems from a solid sleep routine. Sleep supplements can be beneficial adds to your nighttime arsenal, and magnesium (specifically, magnesium bisglycinate) can be a helpful one for a number of reasons that extend far beyond the bedroom.*

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