What’s Up with Magnesium Stearate?

. . . is it helpful or harmful? If you’re a careful supplement label reader, you’ll often see magnesium stearate listed at the bottom under “Other Ingredients.” You may also have heard or seen various warnings about how magnesium stearate is a toxin, that it interferes with digestion and absorption, or suppresses immunity, or generates harmful “biofilms” in the intestines. While some of these claims fall into the category of false marketing hype, there are valid concerns about this much-maligned substance. Magnesium stearate is commonly used as a lubricant in the supplement industry. It prevents nutrients from sticking together, allowing for a consistently maintained mixture, and it prevents ingredients from sticking and jamming the encapsulation machinery. Problems arise when too much is used, when it is improperly applied or when it is impure and of poor quality. Magnesium stearate is not a toxin. It is a combination of one molecule of magnesium with two molecules of a fatty acid called stearic acid, which is very common in the diet. That doesn’t mean, however, that cheap, impure forms won’t contain solvent residues and other toxins and allergens. We solve this problem at Beyond Health by insisting on high standards of purity. Critics point to studies that found magnesium stearate slowed down the rate at which pills dissolved in the body, which would impair digestion and absorption. However handled properly, magnesium stearate will not cause these problems. To make their machines run faster (and save money) some manufacturers add too much magnesium stearate, often as much as 5% of the tablet, which impairs the pills’ ability to dissolve in a timely manner. How long the mixture is mixed and how much heat is generated in the mixing process will also affect how strongly the stearate bonds to nutrients. If done incorrectly, this too will cause problems with how readily the tablet dissolves. At Beyond Health, we use magnesium stearate only when we absolutely have to. Then we assure appropriate dissolution by using only the minimum amount necessary and carefully monitoring the mixing process. As for magnesium stearate suppressing immunity, this claim is really quite outrageous. In one study, a huge amount of stearic acid suppressed the immunosuppressive ability of T-cells in a test tube. This experiment has absolutely no relevance to real life. As for the creation of harmful biofilms, this appears to be mostly an urban legend as there is no scientific data to support it. In fact, as Gene Bruno recently reported in Vitamin Retailer, in one study stearic acid inhibited the formation of biofilms. (Citations for both of these studies are given in the Bruno article). Raymond often warns us that labels don’t tell the full story — not by a long shot. Seeing “magnesium stearate” on a label gives you no clue as to whether it’s a harmful ingredient or not. Dig deeper, or simply buy from vendors you can trust, like Beyond Health!