Magnesium Stearate is in about 95% of all supplements and is hard to avoid. It is there to make machines run smoothly and does not improve the quality of the supplement. On the contrary, it seems.
There are a number of rumours:
Magnesium stearate makes the supplement less effective because it 'forms a capsule' round the active components that make it harder for the body to digest.
Magnesium stearate is often made from cotton plants, which are heavily sprayed.
Magnesium stearate could cause a small layer to be formed in the intestines, which would then prevent many nutrients from being digested (not just the nutrients in the supplements; ALL nutrients you put into your body)
I try to find supplements with no magnesium stearate in it (prudency principle), but sometimes it seems unavoidable. So my question is: is magnesium stearate for long-time use really as bad as the arguments listed above seem to make it? I know most scientists (doctors,...) seem to say it's harmless, but they also say amalgam fillings are harmless too, so it seems stupid to simply believe them.
EDIT: I'm not saying I've got any proof, nor do I personally state that magnesium stearate is harmful or dangerous. I'm just saying I've heard rumours many times, and I wanted to know whether's there's truth in those rumours or not.
asked byBen_16 (734)
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on June 07, 2012
at 12:02 PM
Can we talk chemistry first? Magnesium stearate is the magnesium salt of stearic acid. Stearic acid is a saturated fatty acid. So just based on the chemistry of it all, it's pretty darn safe stuff to ingest. Of course, you could read the Wikipedia page on it and read that magnesium stearate is a major component of soap scum and get scared off.
- Magnesium Stearate quite likely has some effect on the release properties of supplements and medications. That's not necessarily a negative as you've framed it.
- Magnesium Stearate may be sourced from sprayed cotton plants, but it also a highly refined chemical, it's not going to be contaminated with junk.
- Where do you get the idea that mag stearage might form a layer in the intestines? It makes no sense, bile salts are certainly going to solublize it and help with its absorption.
on July 02, 2012
at 05:33 PM
Mag stearate is bullsh, and don't let anyone, despite their chemistry pedantics, tell you different. Some peep ingest 20, 25, 30 pills at once, 2 or 3 times per day! That's an effin lotta stearate! Experiment: Open a capsule with stearate in it, and dump the stuff in water, see what happens. Nothing. it floats there, undissolving. Taste some, work it around the mouth, you can feel the "greasiness" of the stearate. It has no USELFULNESS other than to the machine which make caps and tabs! Here's a simple truth, which, as you age, grows in importance: ANYTHING you ingest must be accounted for, and everything is EITHER good or bad for you. Get a colonic and see for yourself. It's all there, goin thru the system ... Beyond a certain age, say 55 or 60, everything eaten "counts" one way or another, good OR bad--no neutral.
on November 25, 2012
at 03:12 PM
Magnesium stearate is in meat, dairy, poultry, coconut oil, olive oil, grains and many other foods in quantities that VASTLY overshadow the piddling amounts in supplements. This is a con-job people. Wake up!
Here's a good video on this: http://www.youtube.com/watch?v=Fx_ISfVVGuQ
on June 12, 2012
at 08:56 AM
Hi Ben, its a good question but one I dont think we will ever find the true answer too. One thing I would say, if there is any chance that it could affect bioavailability or other detrimental effects, then the real question is why use it at all?
According to a subcommittee of Codex Alimentarius, magnesium stearate has no known use in food, despite its lengthy history of use in supplements, so really it should not be allowed on that basis alone!
on January 13, 2013
at 02:41 PM
Increasingly there is scientific evidence pointing out that magnesium starate, especially mixed with other fatty molecules or with drugs can alter the rate with which the drug or the supplement comes availabel 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 atrticle 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.
on June 13, 2012
at 07:50 AM
I wasnt trying to be positive about Codex Alimentarius, they cause far too much trouble, I was using thier own way of thinking against them but mainly I was trying to show that magnesium stearate should have never been allowed to be used in nutritional supplements, it has not nutritional value at all! :)