What Is Magnesium Stearate?

This is part of our ongoing series helping consumers better understand chemicals, chemistry, and product formulations. We translate the science, bust the myths, and give you an honest assessment, so you can make informed choices for your family!

Ingredient:

Magnesium Stearate

What it is:

Magnesium stearate is a salt created by the reaction of sodium stearate (the salt of stearic acid, one of the most common saturated fatty acids found in nature) with magnesium sulfate (commonly known as Epsom salt) (1,2).

What it does:

Magnesium stearate is most often used as a “flow agent” in supplements, herbal remedies, and pharmaceutical tablets and capsules. Flow agents are an imperative ingredient in these types of products as they help prevent the individual ingredients from sticking to manufacturing equipment and from sticking to one another (3). When dealing with such small particulate matter and creating biologically active products, it’s vital to ensure everything is flowing smoothly to create a final product that is consistent and contains everything it should.

In simpler terms, think of all the individual vitamins and minerals that go into a supplement. All of these ingredients are mixed together and must go through complex manufacturing equipment to eventually become a tablet or capsule – and every tablet needs to have the same levels of each individual ingredient. It’s no easy feat! If ingredients are sticking to the equipment or clumping with one another, your final product will be inconsistent and unreliable.

Not only do flow agents need to be effective at keeping everything moving along as it should, they also need to be inactive/inert, so they don’t react with any of the other ingredients and create unintended effects in the final product or in the consumer. Magnesium stearate effectively and safely performs both of these important functions in many formulations (3).

Magnesium stearate is also used in hard candies and even in baby formulas.

Why we use it:

As mentioned, flow agents are imperative to prevent sticking during the manufacturing of supplements which helps ensure quality, consistency, and premium value. We chose magnesium stearate for our supplements because it’s very effective and has a long record of safety. The FDA’s Select Committee on GRAS (Generally Recognized As Safe) Substances has reported on magnesium stearate safety, concluding that, “There is no evidence in the available information on magnesium carbonate, magnesium chloride, magnesium sulfate, magnesium hydroxide, magnesium oxide, magnesium stearate…that demonstrates, or suggests reasonable grounds to suspect a hazard to the public when they are used at levels that are now current and in the manner now practiced, or which might reasonably be expected in the future (4).”

Magnesium stearate is also approved as safe by Quality Assurance International, Organic Certification, the U.S.D.A. National Organic Program, and by Whole Foods’ Supplement Standards program. Between our research, the approval of these credible institutions, and the approval of our esteemed board of medical advisors, we're confident in the safety of this ingredient as it’s used in our formulations.

Since magnesium stearate can be made from a variety of raw materials, you should know that ours is “kosher” and made from palm oil that’s been certified by the Roundtable on Sustainable Palm Oil (RSPO).

References:

1. Gunstone, F. D., John L. Harwood, and Albert J. Dijkstra. (2007). The Lipid Handbook (3rd ed). Boca Raton: CRC Press.
2. Asgari, M., Fatemi, S., Sotudeh Gharebagh, R. and Haririan, I. (2007), Semibatch Production of Pharmaceutical Grade Magnesium Stearate: A Statistical Approach. Chem. Eng. Technol., 30: 1512–1518.
3. Li, J., & Wu, Y. (2014). Lubricants in pharmaceutical solid dosage forms.Lubricants, 2(1), 21-43.
4. FDA Center for Food Safety and Applied Nutrition. Database of Select Committee on GRAS Substances (SCOGS) Reviews. CFSAN/Office of Food Additive Safety. October 2006.

This post was revised as of 11/23/2015.