MAGNESIUM FOR CONSTIPATION: WHICH IS TYPE IS BEST?

By Lora Jody, RDN,LD

Magnesium is commonly used for constipation, but not every form of magnesium has the same effect on bowel movements. Magnesium citrate, magnesium oxide and magnesium glycinate differ in how they're absorbed and how much magnesium remains in the intestinal tract. Understanding these differences can help determine which type of magnesium may be most appropriate when constipation is the goal. 

Magnesium Citrate

Magnesium citrate combines magnesium with citric acid.

It is commonly used when bowel regularity is the primary goal because unabsorbed magnesium can help draw water into the intestines, resulting in softer stools.

That same effect means too much can produce loose stools or diarrhea.

Magnesium Glycinate

Magnesium glycinate—or bisglycinate—is magnesium bound to the amino acid glycine.

It is commonly selected when magnesium supplementation is desired without a strong laxative effect.

For someone primarily looking for magnesium to support overall magnesium intake while minimizing gastrointestinal effects, glycinate may be preferable.

But if constipation relief is the primary objective, its relatively gentle effect on the bowel may actually be a disadvantage.

Magnesium Oxide

Magnesium oxide sometimes gets dismissed because its fractional absorption is lower than some other magnesium forms.

But that's not necessarily a disadvantage when constipation is the goal.

Magnesium remaining in the intestinal tract can have an osmotic effect, drawing water into the bowel.

In fact, clinical guidelines from the American Gastroenterological Association and American College of Gastroenterology suggest magnesium oxide as an option for adults with chronic idiopathic constipation.

So Which Is Best?

There isn't one magnesium that's best for everyone.

The better question is:

What are you trying to accomplish?

If bowel regularity is the primary objective, magnesium citrate or oxide may be considered.

If the primary objective is magnesium supplementation without producing a significant laxative effect, glycinate may be more appropriate.

More Isn't Better

Magnesium supplements can cause diarrhea, cramping and gastrointestinal discomfort.

Magnesium-containing laxatives also require particular caution in people with impaired kidney function because magnesium can accumulate in the body.

Supplements can also interact with certain medications.

Choosing a quality supplement

Supplement quality matters just as much as the form listed on the front of the bottle.

I've selected professional-quality products that meet the standards I look for in my nutrition practice.

Visit Shop Nutrition to see products selected by Advanced Nutrition Therapy.

This article is educational and does not constitute individualized medical or supplement advice. Consult your healthcare professional before beginning supplements, particularly if you have kidney disease, take medications, are pregnant or have a medical condition.

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