Terry is happy to provide his opinion on diet and nutrition, supplements and lifestyle choices. This information is for educational purposes only. It is not meant to replace the advice of your physician and is not to be considered medical advice, diagnosis or treatment. Should you have any concerns please contact your physician directly.
Q. Dear Terry, “I have heard bad things about a filler used in supplements called magnesium stearate. What is it and is it dangerous? Is it natural or synthetic and why is it in there?” — Lida K., Schoolcraft, MI
A. Dear Lida, Magnesium stearate is considered an “excipient.” Excipients are “helper” substances used in products to achieve specific goals. The excipients are not considered the active ingredient in the product. Some companies call them fillers and binders and try to imply that all of them are bad, but this is not the case. Excipients are just like everything else. Some are good and helpful, some are bad, and some are neutral. A few of the reasons one would use excipients in a product would be to help hold tablets together, keep capsules slippery so they don’t stick in your throat, help products resist moisture, protect ingredients from light exposure, assure dose to dose consistency, and make sure tablets and capsules break down properly after you swallow them and yield up their nutrients—and there are probably a hundred other good reasons to use them that I don’t have space to list. Magnesium stearate is natural, a salt of magnesium and a part of the FDA’s GRAS list (generally recognized as safe). It is used in the manufacture of products to make sure that none of the raw material is lost as it is processed. If you had two tablets, and one tablet lost part of its ingredients because it stuck on equipment and was left behind, you might have two tablets in the same bottle with different doses. One might be 500 mg, and its partner only 300 mg. In order to make sure every single tablet and capsule has the same dose, you need to have ways to protect their integrity during manufacturing and bottling, and magnesium stearate is one of those interventions. In a well-manufactured product, only trace amounts of magnesium stearate are in the finished product. There are also some forms that are much better than others. Magnesium stearate can be of animal origin and I do not prefer that form. I think the best magnesium stearate is from non-GMO plants, and any formula I recommend that uses this excipient will only have it from that kind of source. There are also excipients I would NEVER use. Examples of unhealthy excipients are phthalates. They are not legal in the United States, but occasionally you will see them in finished products imported from overseas. That is why you want to make sure any products you buy are from companies you trust to be ever vigilant watchdogs regarding what goes into their products.
Terry . . . Naturally