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The Most Bioavailable Forms Of Magnesium + What Each One Is Used For

September 8, 2020

Magnesium is an essential mineral that helps keep hundreds of body processes1 humming along.* Maintaining adequate magnesium levels can also help protect us from heart disease, type 2 diabetes, osteoporosis, and migraines, according to the NIH.*

The mineral is present in foods such as leafy greens, avocado, and dark chocolate. However, a National Health and Nutrition Examination1 survey found that 48% of Americans weren't getting enough of it in their diets between 2013 and 2016. Enter: magnesium supplements, of which there are many forms.

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When it comes to magnesium supplements, bioavailability is important.

Every time you take a supplement, some of it gets lost in the body before it gets a chance to do its job. The percentage of supplement that actually makes it into the bloodstream after processing is known as its bioavailability. The higher a supplement's bioavailability, the more effectively it can deliver the intended health benefits.

On its own, magnesium has very low bioavailability. To be turned into a supplement, the mineral is paired with another organic compound that makes it easier for the body to absorb. The resulting combination is either organic, in this case meaning it dissolves well in liquid, or inorganic, meaning it doesn't. Organic forms of magnesium tend to be more easily absorbed2 and therefore more bioavailable.

Inorganic and less absorbable magnesium combinations, such as magnesium carbonate, magnesium chloride, magnesium gluconate, and magnesium oxide, tend to come with certain side effects. "It forms these clusters of water," functional medicine doctor Robert Rountree, M.D., explains in an episode of the mindbodygreen podcast, "and that basically hurries things along in the gut, shall we say."

Yep, loose stools, diarrhea, and abdominal cramping can occur when you take certain kinds of magnesium or when you consume the mineral in high doses. (The recommended cap on magnesium supplementation is 350 milligrams daily for adults.)

The most bioavailable forms of magnesium.

The other organic compound you'll find in a magnesium supplement pairing usually comes with a benefit of its own. This means that choosing the right supplement for you is largely a matter of needs and preference. Here's a rundown of some of the most bioavailable forms of magnesium supplements and what they do.

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4. Magnesium L-threonate

This bioavailable form of magnesium is easily absorbed by the body. It has been shown to have neuroprotective qualities3 in preliminary animal studies, but it's the least researched form of magnesium on the list.

3. Magnesium malate

Magnesium malate, which combines magnesium with malic acid, is relatively easy to digest and it seems to stick around in the body4 longer than other forms of magnesium. It's often taken to ease muscle cramps or treat specific muscle issues like fibromyalgia.

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2. Magnesium citrate

Magnesium citrate is widely considered one of the most bioavailable forms of magnesium5, and it's a laxative that is usually used to treat constipation.

1. Magnesium glycinate

Finally, you have magnesium glycinate, which is a bioavailable form of magnesium that's used to promote sleep.*

"We've been using magnesium to help people sleep forever. And it makes sense," Rountree said on the podcast. "It's a natural muscle relaxant, so it helps the whole body calm down.* It lowers blood pressure.* So it does basically all the things that you want to do to get the body ready for sleep and to help maintain sleep.*" The glycine it's paired with is also thought to promote sleep quality6.*

This is the form of magnesium that mindbodygreen chose to make its first sleep supplement, sleep support+.* The mineral is paired with PharmaGABA, a natural sleep enhancer, and jujube, a fruit used in traditional Chinese medicine for calming and sedation, for a formula that can help people fall asleep faster, stay asleep longer, and wake up feeling restored.* And the glycinate's bioavailability means that these benefits won't be lost on you.*

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Emma Loewe
Emma Loewe
mbg Sustainability + Health Director

Emma Loewe is the Sustainability 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.