Q: I’ve noticed magnesium stearate as an ingredient in some of my supplements. What is it? Is it harmful? Should I be worried about how much magnesium I’m getting between that and my regular magnesium supplement?
A: In a word, no. Let me explain.
Magnesium stearate is a flow agent used in many nutritional supplements as well as pharmaceuticals. Flow agents ensure a consistent dose of a micronutrient or product in each capsule in addition to preventing ingredients from sticking to each other and the equipment used in encapsulating the products. It’s actually a “good manufacturing practice” to use flow agents. Not doing so could result in inconsistent doses of a vitamin, mineral or other product.
Magnesium is a mineral (a very important one!) and stearic acid is a saturated fat found in common foods such as beef, eggs, coconut oil, chocolate, walnuts and human breast milk. Despite the fact that it’s a saturated fat, stearic acid has been shown to have a neutral effect on cholesterol.
A common concern I’ve heard from many people is whether we’re overdosing on magnesium due to the ubiquitous use of magnesium stearate in manufacturing. As described in this article at Nutrition Review, magnesium stearate is composed of one molecule of magnesium and two molecules of stearic acid held together by ionic bonds, making it a salt. This is broken down in an acid environment (like your stomach). The percentage of magnesium is actually only 4% with stearic acid comprising 96%. As you can see, there is no real cause for concern about overdoing magnesium, even if you’re taking a lot of supplements.
And regarding any claims made by some practitioners that magnesium stearate is a chalk-like substance that can prevent absorption of nutrients by gumming up intestines or forming biofilms, this has been thoroughly debunked. So has the claim that it suppresses immune T-cell function. Take a look at this very excellent video by Dr. Dana Myatt, Naturopathic Medical Doctor, as she takes apart those claims one by one.
To your health!
