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Which Type of Magnesium is Best?

My intern who is now Dr. Kristina Burban wrote our magnesium series last spring. Don’t miss part one of the series were she discussed the important role of magnesium in the human body, and evidence for its potential benefit in heart health, diabetes, metabolism, and mood.

I spoke today at a pharmacist continuing education symposium on stress and we talked a lot about magnesium. It’s one of the most common nutrient deficiencies. Magnesium is very helpful to “calm” the central nervous system. In this post, part two, Dr. Burban focuses on the different types of magnesium available in supplements, and the differences between them.

Happy Reading

Dr. Hartzler

Types of Magnesium:

There are many types of magnesium supplements, with different formulations and properties. There are two major types of elemental magnesium: inorganic and  organic magnesium salts. Here, organic and inorganic refer to the type of atom or molecule magnesium is attached to. Inorganic salts of magnesium include magnesium oxide and magnesium chloride, and organic salts include magnesium citrate, lactate, aspartate, and glycinate. 

Supplements that contain inorganic magnesium are harder for the body to absorb, but they contain highly concentrated magnesium. On the other hand, supplements that contain organic magnesium have been shown to be easier for the body to absorb, but contain a lower concentration of magnesium.1 Overall, research has suggested that organic magnesium will lead to more magnesium absorption than inorganic magnesium.1

Magnesium oxide is the most common form of magnesium in supplements, and provides a high amount of elemental magnesium.1 However, the body is only able to absorb about 4% of the magnesium oxide taken by mouth.2 Formulations of magnesium oxide will often contain more magnesium, e.g. 300-500 mg, to compensate for low absorption. Magnesium oxide is more likely to cause diarrhea, because less is absorbed into the body, leaving more magnesium in the intestine to act as a laxative.

The body is able to absorb roughly the same amounts of magnesium citrate, magnesium lactate, and magnesium aspartate. These organic magnesium salts are more easily absorbed than magnesium oxide.2,3 Formulations of magnesium citrate contain less magnesium, e.g. 19-100 mg, since they are more easily absorbed. 

Magnesium glycinate is a form of magnesium that is bound to a protein, causing increased absorption. Magnesium glycinate is thought to be least likely to cause diarrhea. One of our favorite products called Reacted Magnesium contains three different types, DiMagnesium Malate, Magnesium Citrate USP, TRAACS® Magnesium Lysinate Glycinate Chelate. These mineral chelates are much easier to absorb and are not likely to cause gastrointestinal issues. The figure below compares absorption of mineral salts vs. mineral chelates.

There is some evidence that magnesium might be able to be absorbed through the skin by applying magnesium oil or soaking in Epsom salts, but more research is needed to determine if transdermal absorption of magnesium is clinically or significant.4,5

Talk with your primary care provider about what magnesium supplement might be best for you. In general, the organic forms of magnesium and chelated minerals are better tolerated and better absorbed than the inorganic forms. Since magnesium deficiency is very common in the United States, and magnesium has shown to have heart health, metabolism, and mood benefits, consider taking a magnesium supplement or increasing your dietary intake.6 

Did you know our team of clinical pharmacists can help you address nutrient deficiencies by testing and finding out what you specifically need to support your body? You are unique, your life circumstances, your diet, and your DNA. It’s important to find out specifically how to support your body with lifestyle and nutrition. Find out more in our next discovery class or book an appointment today.

The secret code for the giveaway is PHRM2TBL.


  1. Blancquaert L, Vervaet C, Derave W. Predicting and Testing Bioavailability of Magnesium Supplements. Nutrients. 2019;11(7):1663. Published 2019 Jul 20. doi:10.3390/nu11071663
  2. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001 Dec;14(4):257-62. PubMed PMID: 11794633.
  3. Kappeler, D., Heimbeck, I., Herpich, C. et al. Higher bioavailability of magnesium citrate as compared to magnesium oxide shown by evaluation of urinary excretion and serum levels after single-dose administration in a randomized cross-over study. BMC Nutr 3, 7 (2017).
  4. Gröber U, Werner T, Vormann J, Kisters K. Myth or Reality-Transdermal Magnesium?. Nutrients. 2017;9(8):813. Published 2017 Jul 28. doi:10.3390/nu9080813
  5. Kass L, Rosanoff A, Tanner A, Sullivan K, McAuley W, Plesset M. Effect of transdermal magnesium cream on serum and urinary magnesium levels in humans: A pilot study. PLoS One. 2017;12(4):e0174817. Published 2017 Apr 12. doi:10.1371/journal.pone.0174817
  6. King DE, Mainous AG 3rd, Geesey ME, Woolson RF. Dietary magnesium and C-reactive protein levels. J Am Coll Nutr 2005;24:166-71.

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