Magnesium stearate is widely used as an excipient in supplements, dietfood for medical purposes and drugs, because machines compressing tablets run more smooth if magnesium starate is added to tablets.
Basically the addition of magnesium stearate has nothing to do with our body but all with the industriel proces of making tablets.
Magnesium stearate is also the base of Normast tablets, and many people have asked in the past why does Normast which contains the natural and body-own protective fatty compound palmitoylethanolamide, also contains such an unatural fat as magnesium stearate? Magnesium stearate is currently seen as a “hornet into the house” Magnesium stearate furthermore, has been mentioned to cause diarrhea in customers with irritable bowel or lower gut digestive problems.
According to a subcommittee of Codex Alimentarius, the world authority on international food standards, magnesium stearate has no known use in food, despite its lengthy history of use in supplements. A recent report (2010) of the Codex Committee on Food Additives (CCFA) in March 2010 clearly recommended that “magnesium salts of fatty acids” be deleted from the Codex for no known use.
Here we discuss the role of magnesium stearate and give many compelling reasons why it is preferably to choose a supplement without magnesium stearate. This is also the base of the advantage of pure palmitpylethanolamide capsules over Normast, as these capsules are specifally designed to be free of this excipient. Furthermore, other excipients in Normast, such as croscarmellose and povidone are also referred to as not optimal.
Magnesium stearate as a unnatural fat
Magnesium stearate is a body-foreign fat and can be compared with grinded kandle-wax, it is not a natural compound of any food at all. We are thus filling our system with magnesium stearate just because it is easier to compress tablets and the machines producing these tablets can produce more tablets each minute if magnesium stearate is used. A bit odd. Here you see the powder of magnesium stearate:
So this unnatural fat enters our digestive system, and it might make the bio-availabliity of palmitoylethanolamide less optimal, as it most probably forms a fatty impenetrable layers around the palmitoylethanolamide. This has now been shown to be the case for an other natural molecule, predisone, as well as for other drugs. This could be seen via electro-microscopy, we will speak of it in the next chapter. No biological use of magnesium stearate should imply not to take it if possible.
We quote an internet discussant on this topic:
Magnesium Stearate is added strictly for the convenience of the producers and manufacturers of these capsules and formulations.
It is in No way nutritious or added because it is somehow good for humans to consume. It is added for the sake of the machinery, and so the machinery that the herbal powders flow upon, do not get gummed up and stuck.
With the advent of such miraculous additives, we have to hire less people to clean the machines because they flow so much better.
Now what was the reason you bought the product in the first place?
You probably did not go out looking to buy Magnesium Stearate, but there it is, added to our health supplements.
Scientific evidence pleading again magnesium stearate
Increasingly there is scientific evidence pointing out that magnesium stearate, especially mixed with other fatty molecules or with drugs can alter the rate with which the drug or the supplement comes available for our body. Basically if you coat a supplement or a drug in magnesium stearate you are making it more difficult for the body to access the supplement or drug.
Recently, in a lead scientific article on pharmaceutical excipients, it was pointed out that in solid pharmaceutical formulations, magnesium stearate, which is widely used as a so called hydrophobic lubricant, is considered to cause certain manufacturing problems, such as reduction in tablet hardness , prolonged disintegration time [2,3], and retarded drug dissolution [4–6].
A prolonged disintegration time and a decreased tensile strength and all these aspects are clearly seen as disadvantages of Magnesium stearate.
Chowhan and Chi  reported that when Magnesium stearate was mixed with micronized prednisone, a body-own hormone, and a second excipient for 30 min, this prolonged mixing resulted in a decrease in the dissolution rate, and the adhesion of Magnsium starate flakes to the drug particles as a hydrophobic coating was observed using scanning electron microscope (SEM) analysis. This coating compromises the availability of the body-own hormone prednison.
The coating of magnesium stearate has also been seen in a different experiment.
Takeaki Uchimoto et al (2011) followed the technique earlier described by Shibata .They made an electron-microscopic picture of a micronized particle with and without 0.1% magnesium stearate, as you can see on the picture from the work of Takeaki Uchimoto.
Shibata et al.  clarified the mechanism underlying the negative effects of Magnesium stearate concentration on the dissolution rate of drugs using Scanning Electron Microscopy. When even a very small concentration of magnesium stearate, 0.5%, was mixed with glass beads as model supplement or drug particles, a thin impenetrable film of magnesium stearate was formed on the surface of the glass beads.
According to other reports, the formation of these impenetrable films of Magnesium stearate on the surface of micronized drug or supplement particles can also reduce the so called surface wettability. This subsequently reduces not only water penetration into a tablet but also contact between drug and our digestive juices , consequently resulting in a decrease in the surface area that directly contacts with the environment in our digestive tract and a thus decrease the drug dissolution rate.
Recently, in 2012, this again was demonstrated with a lipophylic drug, also like PEA an analgesic, indomethacine. It was coated with magnesium stearate and the dissolution was compared to sodium stearate. The curve clearly shows a much slower dissolution when indomethacine is mixed with magnesium stearate. (after: Dissolution of a poorly water-soluble drug dry coated with magnesium and sodium stearate; European Journal of Pharmaceutics and Biopharmaceutics, Volume 80, Issue 2, February 2012, Pages 443-452, by
Tracy Tay, David A.V. Morton, Thomas R. Gengenbach, Peter J. Stewart)
Health Guru Dr Mercola vehemently against magnesium stearate
One of the leading health guru’s in the USA, the medical doctor Mercola has a whole news issue on the hazards of magnesium stearate in supplements, and we qoute him:
It’s common knowledge that drugs, vitamins or supplements contain more than just the active ingredient. Something has to encapsulate them―hold them together―in a form that not only makes them usable, but producible by a manufacturer in massive quantities.
In the U.S. many supplement makers are adding “flow agents” into their capsules. Their only purpose is to keep ingredients from sticking to equipment during mixing and compression. They make manufacturing faster and easier, but it’s not impossible to produce the final product without them. Not using them simply adds to manufacturing costs and final sales price of the product, but there is clearly no reason this ingredient is added for consumer benefit.
Magnesium stearate is a commonly used and potentially harmful additive found in many supplements. This is a substance I have warned about for a long time because of its subtle ability to cause possible harm to your intestine, possibly even preventing the proper absorption of nutrients.
Potentially Harmful Effects of Magnesium Stearate
Magnesium stearate is formed by adding a magnesium ion to stearic acid. The compound has lubricating properties, which is why it’s often used in the making of supplements, as it allows the machinery to run faster and smoother, and prevents the pills or capsules from sticking to each other.
However, previous research has shown that stearic acid suppresses T cells—your natural killer cells—which are a key component of your immune systemi. According to that study, stearic acid causes the collapse of cell membrane integrity—an effect that was found to be time and dose dependent—which, ultimately, can destroy cell function.
In my view, if you’re taking a supplement, making sure it’s a high quality, natural food-based supplement that does not include potentially harmful fillers and additives such as magnesium stearate.
There are now signs that magnesium stearate might indeed be banned from supplements, and we again quote Mercola:
As recently explained in the featured article, magnesium stearate might be on the verge of getting axed from supplements altogether, which probably would not be a bad thing; at least from a health perspective.
During the March 2010 session of the Codex Committee on Food Additives (CCFA), it was recommended that “magnesium salts of fatty acids” (ie magnesium stearate) be deleted from the Codex, as it has no known use in food….. … and …
for companies that already operate without magnesium stearate, it’s just proof that they’ve been right all along.
Eliminating this component from the product equates to slightly higher manufacturing costs, as the machines cannot run as fast and hence cannot produce as much on any given day. But I believe the increase in cost is well worth it. It’s really important to me to first do no harm, and to take the extra precautions to ensure the products sold on this site are of the highest quality and purity possible.
This is one of the main reasons to select supplements not containing any magnesium stearate: we do not need it in our system and it is of no use to our biology at all…it is just a burden and has many disadvantages, as pointed out.
Some manufacturers now smile, as their supplements are free of magnesium stearate
Some manufacturers may smile at magnesium stearate’s peril. Hypoallergenic supplement companies—such as Thorne Research or Pure Encapsulations—call out their lack of fillers, binders and excipients as a point of differentiation. Also the company Health Leads, with their slogan working with nature avoid all magnesium stearate in their products. The same holds true for JP Russell Science Ltd, who specifically are designing a magnesium stearate free line of products with palmitoylethanolamide.
Dr Mercola’s recommendations for supplements
Dr Mercola makes some statements whcih help the consumers selecting the best supplements. Toxicity of magnesium stearate
Strangely enough, there is not much data on the safety of magnesium stearate, and the data available is not very reassuring. Here a report were we can see that magnesium stearate is definitely not biological neutral and has some unpleasant effects. Of course the dose was much higher than available for human use via supplements, but still the issue is that magnesium stearate has side effects:
Magnesium stearate was fed to groups of 20 male and 20 female rats at levels of 0, 5, 10 and 20% in a semisynthetic diet for 3 months. Decreased weight gain was found in males in the 20% group. Urolithiasis was found in 8 males and in 7 females in the same group. Reduced relative liver weight was seen in males in the 10% and in the 20% groups, and an increased amount of iron was found in the livers of the 20% group. Nephrocalcinosis was reduced in females in the 20% group.
Much data are not available to reassure us. There is only 1 article published on the toxicity of magnesium stearate in Pubmed, the one we discussed here. No other data found, nothing on chronic use and late effects……
References on magnesium stearate
Many data related to the disadvantages of magnesium stearate in supplements and drugs are discussed in the main source of the above mentioned data:
Takeaki Uchimoto et al. A comparative study of glycerin fatty acid ester and magnesium stearate on the dissolution of acetaminophen tablets using the analysis of available surface area. European Journal of Pharmaceutics and Biopharmaceutics 78 (2011) 492–498
Further references on the disadvantage of magnesiumstearate
 W.A. Strickland Jr., E. Nelson, L.W. Busse, T. Higuchi, The physics of tablet compression. IX. Fundamental aspects of tablet lubrication, J. Am. Pharm. Assoc. Am. Pharm. (Baltim) 45 (1956) 51–55.
 O.K. Udeala, J.O. Onyechi, S.I. Agu, Preliminary evaluation of dika fat, a new tablet lubricant, J. Pharm. Pharmacol. 32 (1980) 6–9.
 L.E. Flores, R.L. Arellano, J.J.D. Esquivel, Lubricant susceptibility of cellactose and Avicel PH-200: a quantitative relationship, Drug Dev. Ind. Pharm. 26 (2000) 297–305.
 G. Levy, R.H. Gumtow, Effect of certain tablet formulation factors on dissolution rate of the active ingredient III. Tablet lubricants, J. Pharm. Sci. 52 (1963) 1139–1144.
 K.S. Murthy, J.C. Samyn, Effect of shear mixing on in vitro drug release of capsule formulations containing lubricants, J. Pharm. Sci. 66 (1977) 1215– 1219.
 S.J. Homg, S.K. Kim, Effect of formulation factors on dissolution rate of nitrofurantoin tablet, Soul Taehakkyo Yakhak Nonmunjip 10 (1985) 25–38.
 Z.T. Chowhan, L.H. Chi, Drug-excipient interactions resulting from powder mixing. III: solid state properties and their effect on drug dissolution, J. Pharm. Sci. 75 (1986) 534–541.
 D. Shibata, Y. Shimada, Y. Yonezawa, H. Sunada, N. Otomo, K. Kasahara, Application and evaluation of sucrose fatty acid esters as lubricants in the
production of pharmaceuticals, J. Pharm. Sci. Technol. Jpn. 62 (2002) 133–145.
Appendix: recommendations of an internet doctor in one of the magnesium stearate blogs
I am a doctor and when given the choice between a supplement that contains magnesium stearate and one that does not, all other things being equal, I choose the pure supplement(the one without the machine lube)
Case in point: A pharmacy in my city has a very good Cranberry product that I recommend to my patients.
I like this product because the ingredients are just cranberry powder and the gelatin capsule.
Recently I went to this pharmacy to look for this product for someone and, mixed in with the usual product, I noticed some bottles contained magnesium stearate and silicon dioxide. I am not sure why and I hope that this trend will not continue, otherwise I will be forced to search for another product!
Needless to say, I chose the ones that were without these ingredients. (ALWAYS CHECK THE LABEL)
I am paying for cranberry powder, not for machine lube. There is quite a bit more cranberry powder in the bottle without the magnesium stearate. According to the label, the product was equivalent to 25,000 mg of cranberry fruit, vs. only 17,000 for the product containing the flow agents and machine lube(silicon dioxide and magnesium stearate) This is almost 50% more of the actual product that I wanted to buy for the same price! And since cranberry powder(not magnesium stearate) helps my patients, I rightly purchased the product that contained more cranberry rather than the one crowded out by the offending contaminant.
This quote makes me laugh, especially the little jab at the end: ‘Much of this mis-information (about magnesium stearate) is posted by companies who are trying to differentiate themselves from other vitamin companies by providing products that are free of mag stearate, perhaps because they are not able to compete solely on the actual effectiveness of their products.’
This silly argument absolutely reeks of industry influence. Since it is cheaper and easier to make products that contain magnesium stearate, there is nothing wrong with a company making a product without it and educating consumers about that distinction. If all other things are equal, you wind up with a purer, more potent, higher quality product when the machine lube does not end up competing with the limited space of the capsule. This applies to any herb or supplement.
By principle, choose the pure product! Buyer beware!
Tjandramaga TB, Van Hecken A, Mullie A, Verbesselt R, De Schepper PJ, Verbist L, Josefsson K. Relative bioavailability of enteric coated pellets, stearate and ethylsuccinate formulations of erythromycin. Pharmacology. 1984;29(6):305-11.