Does Magnesium Promote Sleepiness? Experts Weigh In + The 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.*

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.

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.*

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.*

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.