Subject to strict editorial guidelines for selecting sources, we link only to academic research institutions, reputable media outlets, and, where available, peer-reviewed medical studies. Please note that the numbers in parentheses (1, 2, etc.) are clickable links to these studies.
The information in our articles is not intended to replace personal communication with a qualified healthcare professional and is not intended to be used as medical advice.
This article is based on scientific evidence, written by experts and reviewed by our trained editorial team. Please note that the numbers in parentheses (1, 2, etc.) represent clickable links to peer-reviewed medical studies.
Our team includes registered dietitians and nutritionists, certified health educators, as well as certified strength and conditioning specialists, personal trainers and corrective exercise specialists. The goal of our team is not only thorough research, but also objectivity and impartiality.
The information in our articles is not intended to replace personal communication with a qualified healthcare professional and is not intended to be used as medical advice.
One of the most widely used additives in medications and supplements today is magnesium stearate. In fact, you’ll be hard-pressed to find a supplement on the market today that doesn’t contain it—whether we’re talking about magnesium supplements, digestive enzymes, or another supplement of your choice—though you may not see its name directly.
Often called by other names such as “vegetable stearate” or derivatives such as “stearic acid”, it is found almost everywhere. In addition to being ubiquitous, magnesium stearate is also one of the most controversial ingredients in the supplement world.
In some ways, this is similar to the debate about vitamin B17: is it poison or a cure for cancer. Unfortunately for the public, natural health experts, supplement company researchers, and medical practitioners often present conflicting evidence to support their personal opinions, and the facts are extremely difficult to obtain.
It is best to take a pragmatic approach to such debates and be wary of taking sides with extreme views.
The bottom line is this: Like most fillers and bulking agents, magnesium stearate is unhealthy in high doses, but consuming it is not as harmful as some suggest since it is usually only available in extremely small doses.
Magnesium stearate is the magnesium salt of stearic acid. Essentially, it is a compound containing two types of stearic acid and magnesium.
Stearic acid is a saturated fatty acid found in many foods, including animal and vegetable fats and oils. Cocoa and flaxseed are examples of foods that contain high amounts of stearic acid.
After magnesium stearate is broken down back into its constituent parts in the body, its fat content is almost the same as stearic acid. Magnesium stearate powder is commonly used as a dietary supplement, food source and additive in cosmetics.
Magnesium stearate is the most commonly used ingredient in tablet manufacturing because it is an effective lubricant. It is also used in capsules, powders, and many foods, including many candies, gummies, herbs, spices, and baking ingredients.
Known as a “flow agent,” it helps speed up the production process by preventing ingredients from sticking to mechanical equipment. A powder mixture that covers almost any drug or supplement mixture with just a small amount.
It can also be used as an emulsifier, adhesive, thickener, anti-caking agent, lubricant, release agent and defoamer.
Not only is it useful for manufacturing purposes by allowing for smooth transport on the machines that produce them, but it also makes the tablets easier to swallow and move through the gastrointestinal tract. Magnesium stearate is also a common excipient, which means it helps enhance the therapeutic effect of various pharmaceutical active ingredients and promotes the absorption and dissolution of drugs.
Some claim to be able to produce medications or supplements without excipients such as magnesium stearate, raising the question of why they are used when more natural alternatives are available. But this may not be the case.
Some products are now formulated with alternatives to magnesium stearate using natural excipients such as ascorbyl palmitate, but we do this where it makes sense and not because we have got the science wrong. However, these alternatives are not always effective because they have different physical properties.
It is currently unclear whether a replacement for magnesium stearate is possible or even necessary.
Magnesium stearate is probably safe when consumed in amounts found in dietary supplements and food sources. In fact, whether you realize it or not, you probably supplement with multivitamins, coconut oil, eggs and fish every day.
Like other chelated minerals (magnesium ascorbate, magnesium citrate, etc.), [it] does not have any inherent negative effects because it is composed of minerals and food acids (vegetable stearic acid neutralized with magnesium salts). Consists of stable neutral compounds. .
On the other hand, the National Institutes of Health (NIH) in its report on magnesium stearate warned that excess magnesium may impair neuromuscular transmission and lead to weakness and decreased reflexes. Although this is extremely rare, the National Institutes of Health (NIH) reports:
Thousands of cases of infection occur each year, but severe manifestations are rare. Serious toxicity most often occurs after intravenous infusion over many hours (usually in preeclampsia) and can occur after prolonged overdose, especially in the setting of renal failure. Severe toxicity has been reported following acute ingestion, but is very rare.
However, the report did not reassure everyone. Just a quick glance on Google will show that magnesium stearate is associated with many side effects, such as:
Because it is hydrophilic (“loves water”), there are reports that magnesium stearate may slow the rate of dissolution of drugs and supplements in the gastrointestinal tract. The protective properties of magnesium stearate directly affect the body’s ability to absorb chemicals and nutrients, theoretically rendering the drug or supplement useless if the body cannot break it down properly.
On the other hand, a study conducted by the University of Maryland states that magnesium stearate does not affect the amount of chemicals released by propranolol hydrochloride, a drug used to control heart palpitations and bronchospasm, so the jury is still out at this point. .
In fact, manufacturers use magnesium stearate to increase the consistency of the capsules and promote proper absorption of the drug by delaying the breakdown of the contents until it reaches the intestines.
T cells, a key component of the body’s immune system that attacks pathogens, are not directly affected by magnesium stearate, but rather by stearic acid, the main ingredient in common excipients.
It was first described in 1990 in the journal Immunology, where this landmark study showed how T-dependent immune responses are suppressed in the presence of stearic acid alone.
In a Japanese study evaluating common excipients, vegetable magnesium stearate was found to be an initiator of formaldehyde formation. However, this may not be as scary as it seems, as evidence shows that formaldehyde is naturally found in many fresh fruits, vegetables and animal products, including apples, bananas, spinach, kale, beef and even coffee.
To put your mind at ease, magnesium stearate produces the least amount of formaldehyde of all fillers tested: 0.3 nanograms per gram of magnesium stearate. By comparison, eating dried shiitake mushrooms produces more than 406 milligrams of formaldehyde per kilogram eaten.
In 2011, the World Health Organization published a report describing how several batches of magnesium stearate were contaminated with potentially harmful chemicals, including bisphenol A, calcium hydroxide, dibenzoylmethane, irganox 1010 and zeolite (sodium aluminum silicate).
Because this is an isolated incident, we cannot prematurely conclude that people taking supplements and prescription drugs containing magnesium stearate should be wary of toxic contamination.
Some people may experience allergic symptoms after consuming products or supplements containing magnesium stearate, which can cause diarrhea and intestinal cramps. If you have adverse reactions to supplements, you should read ingredient labels carefully and do a little research to find products that are not made with popular supplements.
The National Center for Biotechnology recommends that a dose of 2500 mg of magnesium stearate per kilogram of body weight be considered safe. For an adult weighing about 150 pounds, this is equivalent to 170,000 milligrams per day.
When considering the potential harmful effects of magnesium stearate, it is useful to consider “dose dependency”. In other words, with the exception of intravenous overdose for serious illnesses, the harm of magnesium stearate has only been shown in laboratory studies in which rats were force-fed to such an overdose that no human on earth could consume so much.
In 1980, the journal Toxicology reported the results of a study in which 40 mice were fed a semisynthetic diet containing 0%, 5%, 10%, or 20% magnesium stearate for three months. Here’s what he found:
It should be noted that the amounts of stearic acid and magnesium stearate commonly used in tablets are relatively small. Stearic acid usually makes up 0.5–10% by weight of the tablet, while magnesium stearate usually makes up 0.25–1.5% by weight of the tablet. Thus, a 500 mg tablet may contain approximately 25 mg of stearic acid and approximately 5 mg of magnesium stearate.
Too much of anything can be harmful and people can die from drinking too much water, right? This is important to remember because for magnesium stearate to cause harm to someone, they would need to take thousands of capsules/tablets per day.