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

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.

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 bioavailability2, 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 absorbed3 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 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.

This bioavailable form of magnesium is easily absorbed by the body. It has been shown to have neuroprotective qualities4 in preliminary animal studies, but it's the least researched form of magnesium on the list.

Magnesium malate, which combines magnesium with malic acid, is relatively easy to digest and it seems to stick around in the body5 longer than other forms of magnesium. It's often taken to ease muscle cramps or treat specific muscle issues like fibromyalgia.

Magnesium citrate is widely considered one of the most bioavailable forms of magnesium6, and it's a laxative that is usually used to treat constipation.

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