Magnesium stearate is an additive that’s used in many foods, medications, and cosmetics. It’s also a powder that forms the coating on some pills and vitamins.
It’s a lubricant that helps prevent medicines from sticking together and improving the quality of capsules. It’s called a “flow agent.”
Some people worry that magnesium stearate can keep their body from absorbing nutrients and drugs properly. But that’s a misconception. It’s a safe and common additive in supplements.
There are some concerns about stearic acid coming from cottonseed oil, which is sometimes genetically modified and may contain pesticides that could be dangerous when consumed. However, the chemical structure of stearic acid is unchanged regardless of its source.
Stearic acid is a long-chain saturated fat found in beef, cocoa butter, coconut oil, and other sources. It’s the only long-chain saturated fat that doesn’t raise cholesterol levels.
It also contains magnesium ion, which is essential for healthy body function and a wide range of cellular processes. In the body, magnesium is absorbed in the small intestine and excreted to a lesser extent in the colon.
In cosmetics, it’s often added to makeup or skin care products in the form of a powder that acts as a pacifier and non-gelling thickener. It’s also an anti-caking and film-forming agent.
Studies on the genotoxicity of magnesium stearate in mice show it doesn’t increase the frequency of DNA damage in your bone marrow, and it doesn’t cause any other adverse health effects. The amount you’d have to take to see toxic effects would be so much more than what’s found in supplements, and that’s why I don’t think it’s an issue for most people.