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Confusion About Magnesium Stearate

Please let Dr. Gardner know that I had been very happy with the vitamins.  Today; however, during my research, I came across some information on magnesium stearate. As I read about it and its potential damage to the digestive system, I was feeling grateful that I was taking high quality vitamins. However, after I finished on the computer, I went to look at my bottle of vitamins and found that (yikes!) there IS magnesium stearate in my vitamins.

For that reason, I’ve decided to discontinue my vitamin subscription.  Thank-you for your services and please let me know if any vitamins are produced without magnesium stearate.

Your confusion and concern about magnesium stearate is easy to understand, especially given the “controversy” that abounds on the internet.  First, let me set your mind at ease, and then I’ll explain the truth about magnesium stearate.

There is no research in humans that shows any negative effect of magnesium stearate in the human population.  It is unclear if the companies marketing “magnesium stearate-free” nutritional supplements are based on misunderstanding or willful misinterpretation of data, but they clearly are trying to gain a marketing advantage and not trying to disseminate the truth.  Anyone who has had any anxiety about the use of magnesium stearate in my Primivia supplement line can relax and be confident of its high quality.

Magnesium stearate is used in the production of foods, cosmetics, medications and nutriceuticals. Stearic acid is an 18-carbon chain saturated fatty acid, and the stearate form is a safe isomer of the fatty acid.  Although not mentioned, magnesium palmitate is also used for the same purpose, and is a higher concentration than stearate.  Palmitate is a 16-carbon chain saturated fatty acid.  Both the stearic and palmitic acids in magnesium stearate are derived from natural, edible sources.  The normal ingestion of stearic acid in food on a daily basis is about 7,000 mg.  If you were to take 20 tablets of nutritional supplements that weighed about 1,000 mg each, you would ingest 300 mg of stearic acid, less than 5% of a normal daily intake.

There have been some rat studies and in-vitro studies (in test tubes) with magnesium stearate that showed two potential problems.  One is that it affected the immune system.  However–and this is a big however– although rats are usually tested before humans because so much of their physiology is like humans, this is not so with the stearic acid.  Rats do not have the enzyme to break down stearic acid into the 18-carbon oleic acid with one double bond.  This means the stearic acid builds up to toxic levels in rats in these studies.

The other potential problem with intake of fat is that it could slow down the breakdown and absorption of nutrients, including supplements.  Two randomized studies done on the medications propranolol and metoprolol with three levels of magnesium stearate levels in the product showed no difference in bioavailability.

8 thoughts on “Confusion About Magnesium Stearate

  1. Dr. Gardner is saying what any mainstream doc would say. As a nutritionist, I try to buy all (or at least most) of my vitamins without magnesium stearate. There are several brands that don’t have this in them:
    Garden of Life’s raw vitamins which you can get for a very reasonable price at

    You can also order from: (and recommended by Dr. Carolyn Dean — MD and ND) (also has a superior green powder)

    Hope these help.

    1. Suz, I don’t know why you would recommend I just went there and the very first vitamin I looked at had the following:

      Other Ingredients: Gelatin (capsule), rice flour, stearic acid, magnesium stearate and silicon dioxide.


      I went no further.

  2. It is important to note that Dr. Gardner is Not a “mainstream” doc, having achieved the Certified Nutrition Specialist designation, which is the highest achievement in the scientific field of Nutrition. Further, the generic term “nutritionist” has no value in the field of Nutrition & Food Science, and according to the American College of Nutrition anything less than a Registered Dietitian is merely a Salesperson. I will continue to take Dr. Gardner’s supplements because having done thorough research & personal testing, I have found them to be both high quality and moderately priced, but most of all, I Feel Better.

  3. Ouch! Calling me a mainstream doc hurts. I am always open to dialogue–show me the research that shows any harmful effects of magnesium stearate in humans so I can review it.

  4. I want to come to the seminar on June 25, Please give me more info and when and who do I pay

  5. Melvin,
    Perhaps you could direct me to a study showing magnesium stearate as harmful. I’m not looking for opinions. I want “facts” or at least studies. I’ve been looking off and on for weeks and have found nothing legitimate and not self serving.

  6. Hey Doc, there may well be no scientific research on magnesium Stearate, but that doesn’t mean people aren’t having allergic reaction to it.
    First of all, it’s the stearate part that is the problem. So, whether its magnesium, calcium or zinc Stearate makes little to no difference to anyone who is allergic to it and what exactly we are allergic to is the cotton oil used to make the Stearate. Why? Because cotton has been genetically altered to accept chemical pesticides and herbicides, which then become a physical part of the plant. When the oil is extracted from it, it contains the residue of these chemicals. In small amounts to be sure, but, obviously, enough so that some of us react to it.
    Personally, I’m so sensitive to Stearates that just one pill will cause blisters to appear on my hands and feet within just a few hours. Yet it will take a few weeks to get over it.
    So you’re right, the medical researchers have not found the link, but the rest of us have. My doctor (allergist) and I have proven time and again, that I am allergic to Stearate. Period.
    So now what???

  7. Hello,

    I was told that Magnesium sterate is or has hydrogenated plant material. I don’t want to consume anything that is hydrogenated, as it is well documented that hydrogenated oils and fats are extremely bad for humans. Can you clarify? Thanks!

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