Does Your Magnesium Glycinate Contain Magnesium Oxide?

Published on February 15, 2017 by Dr. Paul Hrkal

Something Isn’t Adding Up: Does your Magnesium Glycinate also contain Magnesium Oxide?

Magnesium is one of the most used natural health products for good reason, it does so many beneficial things. It relaxes tight muscles, calms nerves, widens blood vessels and reduces inflammation just to name a few. From a physiological perspective, it is one of the key lynch pins of your cellular energy production so it is no surprise it has so many applications. To learn more about why magnesium is such a common deficiency click here.

Being a practitioner that uses magnesium with most of my patients I wanted to clarify a few, very important, points that recently have come to my attention regarding magnesium products and the increasing amount of elemental magnesium. Below is a summary of the different forms of magnesium and the % of magnesium in each form.

Magnesium Form % Mg Description and Summary Key Clinical Uses
Mg oxide 58% Commonly used in OTC laxatives Laxative
Mg citrate 11% Commonly used form – good absorption but still can be laxative Laxative, general magnesium support
Mg (bis)glycinate 11-14% Amino acid glycine has calming effect on nerves Insomnia, restless legs, anxiety, muscle spasm
Mg malate 11% Malate increases energy production inside cell Fibromyalgia, muscle pain
Mg aspartate 7% Aspartate helps transport fats inside the cell Chronic fatigue
Mg taurate 8.8% Normalizes electrical activity across membranes in heart and brain Cardiovascular diseaseArrhythmia
Mg orotate 7.2% Orotic acid also increases the formation of RNA and DNA, which can help repair damage to heart cells, improve stress tolerance and therefore improve function HypertensionCongestive Heart Failure Mitral valve prolapse Stable angina Blood vessel elasticity
Mg theronate 8.1% Studied to penetrate past the blood brain barrier Brain injuries, cognition, memory, focus

To read more about magnesium and the different forms check out my article about different types of magnesium

One of the most popular forms is magnesium glycinate. Recently, I have noticed that several magnesium glycinate products claim to contain 200mg of elemental magnesium. We obviously want higher amounts of elemental magnesium but this immediately raised some red flags because dosage calculations just don’t add up.  As you can see in the above chart, the percent of elemental magnesium for magnesium glycinate is 11-14%. If you consider that the maximum you can fit into the standard capsule (largest 00 veggie cap) is 850mg, this means the maximum elemental magnesium would be 100-120mg.

You are probably asking how is it possible to get 150 or 200mg of magnesium glycinate per cap? The label clearly states magnesium glycinate as the only medicinal ingredient. The only plausible answer is it’s NOT pure magnesium glycinate. What else is it then? The likely culprit is magnesium oxide, with a much higher percentage (58%) of elemental magnesium, could be combined with magnesium glycinate to inflate the “total elemental magnesium content” on the label. While adding magnesium oxide to magnesium glycinate is not going to harm a person, it may increase the likelihood of having loose stools without increasing magnesium levels effectively. Further, these blended forms are rarely labelled clearly on products, meaning consumers are led to believe that are getting a pure form of magnesium glycinate. Sometimes magnesium oxide is listed as a non-medicinal ingredient (which also is a sneaky way of not fully disclosing it) or it is not listed at all.

There are 2 possible explanations for this problem. Either a supplement company is aware and has decided to exclude it on the label or the raw material supplier is mislabeling the product and the supplement company is unaware of this fact. The second scenario has even led to a lawsuit in the United States where suppliers were found to be selling magnesium glycinate which included oxide in a proprietary form that is labeled as a “chelated” form of magnesium. The trouble with a proprietary form is that manufacturers don’t have to disclose all the ingredients. In the case of the lawsuit mentioned the blended form of magnesium contained mag glycinate, mag oxide, maltodextrin, citric acid and silica. Supplement companies in this case were unaware of the misidentification as it would not be reflected on the certificate of analysis (a lab test that checks the ingredients and contamination. Either way, neither reason is an acceptable excuse.

How is this allowed to happen? For regulatory bodies, such as Health Canada (Natural Health Product Directorate NHPD), this sort of violation is lower on the priority list for dealing with complaints as there is no imminent health threats, i.e. allergen potential or adverse reactions. As far as the regulatory bodies are concerned, the company has a license to sell magnesium and is selling magnesium. The form of the magnesium is considered to be nuance. The concern speaks to a larger issue in the natural health product industry. Consumers of natural health products have a right to knowing exactly what is in a product they are purchasing. Cutting corners to make more money or being ignorant about what’s in a product they are selling is no longer acceptable. This is exactly what gives the whole industry a bad name when investigations and media outlets uncover shady ethics and adulterated products. As an industry that is still evolving its standards and that has been riddled with scrutiny for efficacy and safety, it benefits the entire industry when supplement manufacturers thoroughly vet their suppliers for medicinal and non-medicinal ingredients and then clearly communicating that with their customers.

What can you do? Start to understand how to read supplement labels. Check the non-medicinal ingredients and look for magnesium oxide. Beware formulations that contain ingredients that explicitly state modifications like “buffered” magnesium glycinate. This can be code for “mixed with something” that you might not want. I would also be wary of doses of magnesium glycinate above 125mg. As a savvy consumer, you have a right to hold your supplement company accountable so you can trust them with your health.


Coudray C, Rambeau M, Feillet-Coudray C, Gueux E, Tressol JC, Mazur A, Rayssiguier Y: Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg- depleted rats using a stable isotope approach. Magnes Res 2005;18:215–223.

Copeland et al v. Albion Laboratories, Inc.; Seeking Health, LLC; and Designs for Health, Inc., Case No. 15-cv-585, W. D. WA.

  • Susan

    I was on website but they don't carry the Magnesium Mg (bis)glycinate, I wanted to get my
    Mg aspartate and to save shipping costs order them together!

    Do you know of another good Canadian online supplement supplier that would carry nothing items.

    Thank you for free article about the different types of magnesium. My husband and I are both suffering and there are products that hopefully help us both!

    I'm becoming increasingly frustrated and nervous as I'm not sure which company I can trust like I feel with AOR, If I need to get help from another area can you please tell me what I should do next!

    Thank you.for any assistance that you can give me! Susan

  • Shelia

    What does magnesium carbonate do?

    • Hrkal


      It really does nothing beneficial. See my response to your other post.

      • Shelia

        Thank you so much. I found it again under the other article.

  • Corey

    I see many products labelled magnesium glycinate lysinate chelate. Your chart does not list this item. What is the differance between magnesium glycinate and magnesium glyinate lysinate chelate if any.

    • Hrkal

      Hi Corey,

      I am not familiar with this product but beware anything that states its a chelate. This is how manufacturers mix in inferior types of mag.

      See my article for more info.

      Dr Paul Hrkal ND

  • Man D

    Thank you so much for bringing this issue to my attention, and the attention of others. It inspired me to research the product I have been using, and it seems they are using oxide in addition to glycinate, without CLEARLY reporting the issue. Indeed, it appears they are making the issue ambiguous on purpose. I will be switching to AOR's product as a result. Thank you so much for spreading the word and educating us.

    • Aky

      [Comment awaiting moderation]

  • Bill McEachen

    Great information on magnesium!! My wife has short term memory loss . What AOR products would feed the brain,improve memory perhaps improve sleep.? Also during the night we have bathroom visits.. Any suggestions on products or on finding reliable information will have our heart felt thanks to say the least.WJM

    • Hrkal

      Hi Bill,

      I would suggest magnesium L-theronate if most interested in brain support (AOR doesn't make this form) or use mag + taurine. Taurine is very helpful for both sleep and the neuro function.

      Dr Paul Hrkal ND

  • John

    Re: Mg The info is usually accurate on the web links but often lead to them selling or promoting a product ie Biased in there direction and may lead to consequences Mg can be dangerous over it's UL. Everyone would be well advised to search on supplement in question which also lets one know if you even need it (ie CoQ10 which your body makes on its own) I was excited about Mg Asparate until reading up on it. Going to go with Mg Malate made in USA (be nice if it was USP verified NSF suppliers were expensive The cGMO insignia on label has stringent requirements for label accuracy and quality) With all thats out there, it's comforting to know the US and Canada have stringent regulations (as long as their followed) Do you point people towards trustworthy labelers as far as vitamins and minerals go (Mg Malate) ? Went with USP verified Kirkland Signature Multi which is 100 % only on most ingredients and TruNature Probiotics, both thru Costco on line and great price. Thanks jfc BTown, MA

    • Hrkal

      Hi John,

      Excellent points that you should use brands with the highest quality standards. Look for GMP manufacturing. I use only professional brands made in US, Canada or Europe. The most important think you should look for in mineral supplements is 100% fully reacted. That means it only contains the mineral stated on the label.

      Dr Paul Hrkal

  • Jon

    Wow! Now I understand why I seen Elemental after the Magnesium for ingredients. Had no idea what it meant until now. Thanks so much for providing that information! Now I am looking for a reliable magnesium glycinate supplement. Do you recommend any? Also, about how much food would you need to consume to get the daily magnesium value? I prefer it the natural way, but currently having issues with tingling in body and warm feet and hands. Dr told me to take magox but well the laxative effect.

    • Hrkal

      Hi Jon,

      I am glad you found it helpful. Look for a magnesium glycinate supplement that is about 90mg of elemental glycinate per cap. That is the max amount you can fit. There really are no food amounts that are equivalent to supplements. Nuts and seeds, tofu are high but are not as bioavailable. Pumpkin seeds are the highest and are great to add to granola and salads.

      Dr Paul Hrkal

  • Ericka

    If you had a stroke that affected the left side of your brain, and it damaged your eyesight and made you deaf, would magnesium help? And if yes, which one or ones are best?

    • Hrkal

      Hi Erika,

      Magnesium would help in a supportive way since it improves blood flow. Any well absorbed form like glycinate or taurine would be helpful. More specific nutritional interventions would be needed to really make a difference. Vitamin E, Vinpocetine, and citicoline would be top of my list to look into. A Naturopathic doctor would be able to help you with this protocol.

      Dr Paul Hrkal ND


  • Elizabeth

    What type of magnesium will not cause a laxative effect?
    Thank you,

    • Hrkal

      Hi Elizabeth,

      All magnesium has the potential to cause loose stools. Mag oxide will just cause it much sooner then forms like mg glycinate or malate. You can get to higher dose before loose stools occur with these forms which means more magnesium is absorbed and there is a greater therapeutic effect.

      Dr Paul Hrkal ND