Magnesium Stearate FAQs

March 31, 2016
Magnesium Stearate

Why is magnesium stearate used in some products?

Natural ingredients don’t always smoothly flow through processing equipment and manufacturers need to utilize excipients like stearates to fill capsules or form tablets. Magnesium stearate is the most desirable natural flow agent. Pharmaceutical companies and non-natural manufacturers use synthetic flow agents, such as di-calcium phosphate.

Is magnesium stearate toxic?

No. Magnesium stearate is safe, not toxic. We have extensively investigated the safety of magnesium stearate. Allegations of toxicity have been circulating for over 20 years. We have found the “evidence” to be misleading because it is either largely circumstantial based on test tube studies that don't accurately represent the data observed in human clinical trials or based on theoretical dangers (such as a type of processing that is not commonly used to make stearic acid from unsaturated fats). Either way, the reality of dietary fats in the human body is quite different than what these theories present.

Are stearates and stearic acid naturally found in foods?

Yes. Stearic acid (stearate) is the predominant saturated fat in the human diet. Stearates are nutrients that represent a natural part of every type of fat, whether animal or vegetable, and are typically consumed in amounts of several grams per day from common food sources. A 200-calorie serving of dark chocolate can contain up to 5 grams of stearates; cocoa butter, coconut oil, beef fat, olive oil, and virtually all fats and oils naturally contain far more stearates than do dietary supplements

What is stearic acid (stearate) and what happens to it in the body?

Stearate is one of the major saturated fatty acids in mammals and is acquired through two pathways: 1) dietary fat absorption and 2) de novo lipogenesis (our bodies make it from other dietary fats) Stearic acid is largely converted to oleic acid by the liver; which of course does not happen in a test tube study.

Are there any known risks of consuming stearates?

Stearates do not share the cardiovascular risks of other forms of saturated fat. Stearates are well absorbed and do not coat the G.I. tract (in fact they discourage certain undesirable biofilms), so comparatively tiny amounts in dietary supplements do not inhibit absorption of nutrients in vivo (in live people)

What is magnesium stearate?

Magnesium stearate is a form of chelated/preacidified magnesium, and just like other chelated minerals (magnesium ascorbate, magnesium citrate, et al) has no inherent negatives based on its being in a stable neutral compound comprised of a mineral and a food acid (vegetable sourced stearic acid neutralized with magnesium salts)

Are stearates hydrogenated?

Stearates can be produced by hydrogenation. However, there is no need to manufacture stearic acid from cottonseed or other liquid vegetable oils using hydrogenation to artificially saturate the fatty acids. At NOW Foods, we use non-hydrogenated palm oil that already contains significant amounts of saturated fats providing abundant stearic acid. We use pure USP-grade magnesium stearate derived from non-hydrogenated, non-GMO, non-irradiated, certified Kosher palm oil.

Is NOW Foods working on substituting magnesium stearate in its products?

NOW is reformulating some products with alternatives to mag stearate, using such natural excipients as ascorbyl palmitate, but we’re doing it where it makes sense and not because we misunderstand the science. These alternatives don’t always work, though, having different physical properties.

Where can I find additional information on stearates and excipients on your website?

  • /Quality/Quality-Notes/M093528.htm
  • /Quality/Quality-Notes/099446.htm

Where else can I find reliable information on stearates?

What has Dr. Ray Sahelian, MD, who has one of the most visited websites in the world on the topic of dietary supplements and natural medicine maintained and written by a medical doctor, written about stearates?

“There is no evidence that small amounts of stearic acid are harmful. If anyone knows of a human study that indicates magnesium stearate, in the small amounts found in capsules, has shown to have harmful effects, email me. I have searched extensively and not seen any such clinical trials. I believe there is misinformation on web sites that claim this substance is harmful…Much of this mis-information is posted by companies who are trying to differentiate themselves from other vitamin companies by providing products that are free of mag stearate, perhaps because they are not able to compete solely on the actual effectiveness of their products. If anyone tells you magnesium stearate in the extremely small amounts found in capsules is harmful, challenge them to provide you with a human study that proves their point -- they will not be able to.”