Magnesium Stearate: An Honest Look

Magnesium Stearate has earned a really bad rep in the spotlight, as part of the dietary supplements industry. While we, personally, don’t use MS in our supplements – which is our judgment call – we understand that there are two sides to every story. We believe that knowledge is power and since we secretly want to be superheroes, we tend to surround ourselves with loads of information. So it’s time to take you to school, boys and girls. Let’s learn about Mag Stearate…

What is Magnesium Stearate?

The Basics:

  • Magnesium Stearate, AKA: ostadecanoic acid, magnesium salt
  • Chemical Compound
  • White (solid) substance at room temperature, typically a powder
  • Considered an “inactive” ingredient (or toxin)
  • FDA-Approved inactive ingredient used for its lubrication qualities and as a diluent

But really, what is this stuff?

Magnesium Stearate forms when Stearic Acid (a fatty acid) joins with Magnesium. It is derived from both plant and animal oils. However, plant sources seem to be more popular. In the plant form, it is made from Hydrogenated Cottonseed or Palm oil.

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Believe it or not, MS is a major component of “bathtub rings;” when mixed with soap and hard water, MS and Calcium Stearate (typically already in tap water) form what is commonly known as “soap scum.” Yummy!


Lubrication qualities. Manufacturers add MS to their formulas because of its natural lubrication qualities. In essence, it helps keep the machinery clean of buildup and keeps the agent flowing. In turn, this can save costs on production from not having to stop the process to clean off the machinery. This also keeps the formula mixture consistent due to the lack of “clumping.”

Low amounts are used in supplements. In reality, less than 1% of MS is used in supplements. In super small doses, MS is potentially harmless. This makes many question what all the fuss is really about.

No human studies show any potential “danger.” There hasn’t been any human studies done to show any potential harm on our health.


Studies done on rats show tumors, liver toxicity, kidney stones
The thing about MS is that it builds up in our bodies. In a numerous amount of studies done on rats, they found tumors, liver toxicity and kidney stones from the use of MS. Why do we care what side effects there are in rats? Well… rats are used in medical testing because their genetic, biological, and behavior characteristics closely resemble those of humans, and many symptoms of human conditions can be replicated in mice and rats. “Rats and mice are mammals that share many processes with humans and are appropriate for use to answer many research questions,” said Jenny Haliski, a representative for the National Institutes of Health (NIH) Office of Laboratory Animal Welfare.

Unnecessary. The use of MS in our supplements is strictly for manufacturing purposes. There is no nutritional benefit to adding Mag Stearate to supplements. This means that companies are putting substances in our supplements that are unnecessary and useless for our health.

Magnesium Stearate is also used to dilute products. It is very rare that a company can’t find a different solution to having a potent mixture, MS should not be the first resort to this problem. In reality, many companies use it to dilute the product and sell it at a marked up price. Such a shame.

1+1=2, 2+2=4. Back to that 1%…. Okay, so your daily multivitamin only has 1% Magnesium Stearate, but so do your Amino Acids, as well as your protein powder, AND the melatonin you take at night. Soon enough that 1% turns into 4%. The more supplements you take with Mag Stearate in them, the more you are putting into your body. At what point does it become a health risk?

You Decide

Just as we feel you have the right to choose what is in your foods, we feel you should decide if Magnesium Stearate is something you want in your life. The population seems to be split on their thoughts between the “old school” way and “how it’s always been done” with the “new school” folks who want to know what’s going into their bodies. Either way, knowledge is power; with the pros and cons laid out for you, you decide.

What are your feelings on Magnesium Stearate? Shout them out on Twitter! @BioTerraHerbs #goherbal

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