MSG myths debunked with real science

Updated 12 April 2015

Updated 5 December 2014

Food additives are one of the most passionate issues amongst people who eat (which would be everyone). AspartameHigh fructose corn syrup. GMO‘s. Salt. Sugar. Trans fats. Polysorbate 80. Some of the angst caused by these additives is that they have scary chemical names.

Obviously there is a “low fructose corn syrup” that has got to be better and healthier? Right?

However, there is one food additive that appears to be the root of all evil–MSG. How many times have you been to a Chinese restaurant where they put up signs with NO MSG ADDED?

Just so you know, unless that restaurant isn’t using soy sauce (one of the major components of nearly all Chinese food flavorings), the amount of MSG in your Kung Pao Chicken is still quite high, because that soy sauce has more MSG in it than could possibly be added by a shaker of MSG.

MSG myths debunked. It’s time.


MSG has no taste by itself, but it is used by many professional cooks as a flavor enhancer, improving and enhancing the flavor of almost any food. The taste that is enhanced by MSG is different than the standard sour, sweet, bitter and salt flavors–it is called “umami,” which also is enhanced by substances like soy sauce. It’s the savory flavor that one finds that is different from the commonly stated “four tastes” that chefs used to consider when developing flavors for food.

The taste enhancing quality of MSG is not well understood, but it’s possible that humans evolved the pleasurable taste of umami as a result of natural selection favoring those who enjoy eating high quality protein foods.

MSG has been used as a flavor enhancer for several thousand years. It is one of the key components of many Asian cuisines, especially Japanese who have extracted MSG from kelp for centuries. The Romans used a sauce called garummade from fermented fish, that was used instead of more expensive salt. In fact, MSG can be used to mask bad flavors, such as spoiled meat, just like salt.

So, before we get anywhere down this debunking trip, MSG wasn’t invented by Monsanto and forced down the throat of innocent people everywhere. It’s been a flavor enhancer for a few millennia.

The Myth

The myth of MSG probably started with personal anecdotes after eating Chinese food. A 1969 article in Science claimed there was a dose-response relationship between Chinese food and the Chinese Restaurant Syndrome (CRS).  But the study did not isolate MSG as the cause, and was not blinded (which would be nearly impossible if were to determine if the cause was the food rather than the ingredients).  Unfortunately, the study has never been repeated, so it’s impossible to determine if it provides evidence that Chinese food does anything, let alone MSG.

Joe Mercola, one of the leading purveyors of nonsense science and medicine, calls MSG “the silent killer lurking in your kitchen cabinets.” Oh my.

His claims are based on a belief that MSG is an excitotoxin, which causes a pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters. This pseudoscience is promoted by  Dr. Russell Blaylock, a board-certified neurosurgeon and author of “Excitotoxins: The Taste that Kills.” Setting aside the Appeal to Authority (a board certified neurosurgeon may not have any actual knowledge of neurochemistry), a book isn’t necessarily a high quality source.

Mercola pushes a belief that MSG overexcites your nerve cells to the “point of damage or death, causing brain damage to varying degrees — and potentially even triggering or worsening learning disabilities, Alzheimer’s disease, Parkinson’s disease, Lou Gehrig’s disease and more.” Oh my!

But Mercola doesn’t stop there. He also believes that MSG causes obesity, eye damage, headaches, fatigue, disorientation, depression, and a whole host of other maladies. And he states that up to 40% of the US population may be impacted by MSG. OH MY!

Real Science

First, what exactly is MSG. This is the point that makes many scientists laugh, because MSG is simply the sodium salt of glutamic acid, an amino acid which is the building block of proteins. You get glutamic acid from almost every food you eat from grains to meat. Some grain proteins have over 30% by weight glutamic acid. Since glutamic acid doesn’t exist except in the presence of water, it precipitates with sodium or other cations (potassium, lithium, and others).

Hence, the “monosodium” part of MSG. Precipitated salts do not change it’s essential chemical nature.

Here’s the actual science behind glutamates (you can ignore this paragraph, if chemistry makes your eyes glaze over). When glutamic acid or one of its salts is dissolved in aqueous solutions, a pH-dependent instantaneous chemical equilibrium of the amino acid’s ionized forms, including zwitterionic forms, will result.

These forms are called glutamates. Salts exist only in a dry and crystallized form. The form ultimately responsible for the taste is the glutamate ion, and the form of glutamic acid at the time of the addition is not important. However, crystalline glutamic acid salts such as monosodium glutamate dissolve much better and faster than crystalline glutamic acid, a property important for use as a flavor enhancer.

Glutamic acid, one of the amino acids upon which every single protein is built in the human body, is chemically indistinguishable from the acid salt, MSG. Once you ingest MSG, it dissociates into sodium and the glutamate, which will be absorbed and utilized by the body.

Glutamic acid does not suddenly change properties when in salt form. Once it’s consumed, the glutamate separates from the sodium, and binds with hydrogen to become an acid again. The sodium is either utilized by the body or excreted through the kidneys.  It’s a simple physiological process, no mystery at all.

Let me repeat myself, just for clarity. Ingest MSG into the liquid environment of the stomach, and it simply dissociates back into one sodium ion and one glutamate ion, and the glutamate is absorbed into the blood to create new proteins. It’s very simple chemistry, about the simplest I could describe in human physiology.

The body produces glutamate (or glutamic acid more properly) during various cellular processes, including the citric acid cycle, or Kreb’s cycle, which is a complex metabolic system fundamental to how the cell builds proteins and provides energy.

Glutamate is also a key compound in eliminating and controlling the waste nitrogen in the body (which is created by cells in the form of urea). It is also a neurotransmitter, used by nerve cells to transmit certain types of information, and is a critical substance in cognitive functions in memory and learning.  In other words, glutamate is very important to your life.  Without it, you will probably die. Or at least not be able to think.

So if you eat a lot of glutamate in your food, and your body synthesizes glutamate in substantial quantities, what is bad about MSG. Well, there’s a couple of issues that might happen. MSG does have a sodium, but it’s actually less by weight than an equivalent amount of table salt. Interestingly, in a 1984 Journal of Food Science article, MSG may actually be useful in reducing sodium consumption while not compromising taste (salt is critical to taste of many savory foods).

And that’s about it.

Best evidence

But is there any evidence that MSG is dangerous to humans?  In a word, no.

These review articles, which are meta-analyses of a large number of primary research articles, along with clinical trials, just don’t support the myth that MSG has an effect on anyone. There might be a small subpopulation of people who are sensitive to MSG, but even that has little support in scientific evidence, and is completely dismissed in systematic reviews.

About that Chinese Restaurant Syndrome.

It is possible that Chinese food itself causes CRS. The food is saltier. It is filling. It can be high in carbohydrates and oils. In other words, other substances within the food may have the same exact effect as what is claimed by MSG alone. Funny thing is that soy sauce is higher in free glutamate (as discussed above, the form of MSG in solution) than what is used by most cooks. So are tomatoes. So are dozens of other foods.

In fact, according to a report by Food Standards Australia New Zealand, a typical Chinese restaurant meal will have between 10-1500 mg glutamate per 100 g food. Soy sauce has 400-1200 mg/100g. Vegemite (for my Australian readers) has about 1400 mg/100g. Parmesan cheese has around 1200 mg/100g. Tomatoes have around 200 mg/100g. In other words, your typical Italian meal (with tomato sauce and Parmesan) may provide more glutamate than your typical Chinese meal.

The TL;DR version

MSG is just a simple salt of glutamic acid, one of the 20 or so amino acids that are the building blocks of every protein in the body. The glutamate in MSG is indistinguishable, even at the atomic level, from all other glutamates on the planet. All of them. The glutamate in seaweed or manufactured from some process in a lab are equivalent to the ones produced by humans.

Almost everyone who claims an MSG sensitivity does not base that on anything but their personal experience. Anecdotes. They remember the one time that they might have had MSG, but forget all the times they felt fine after having sushi with soy sauce. Or a BBQ sauce that contains soy sauce and tomato sauce.

MSG is perfectly safe.  Go have a spoonful. Or put it on your food, because it does make it tastier. But it isn’t going to hurt you, unless for some illogical reason you think

Key citations


  • MariusDejess

    “MSG is perfectly safe. Go have a spoonful. Or put it on your food,
    because it does make it tastier. But it isn’t going to hurt you, unless
    for some illogical reason you think.”

    Can anyone prove from some kind of double-blind tests that MSG really enhances food flavors?

    I have just tried again yesterday to see whether it adds flavor to for example noodle, but no, nothing of flavor except what ordinary salt imparts, saltiness.

    Tell me your own double-blind tests: put cooked spaghetti in two completely look-alike bowls, add MSG in one and not in the other, take notice which has MSG; now ask someone to taste the spaghetti in both bowls, and tell you which one has any taste at all, and what is the taste.

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  • Shawn Parella

    I think it is incomplete to simply say that MSG is not “dangerous to humans” without acknowledging animal research, where far more invasive experiments can be performed. MSG has been shown to cause neuron swelling and rupture in mice. As for the blood brain barrier crossing, “Although the blood brain barrier (BBB) has low permeability to MSG, the presence of high affinity glutamate transporters located at the BBB capillary luminal membrane could facilitate the uptake of MSG into the brain.” Nothing definitive here, but enough for me to keep an open mind.

    Deciphering the MSG Controversy

    • Skeptical Raptor

      Animal studies just have no relevance. Unless we can provide real evidence in the form of clinical trials, then you’re relying upon the precautionary principle which is irrelevant to me.

      Once again, glutamate is an amino acid. Please convince me that a simple amino acid, which is part of every single protein on this planet, can be harmful.

      BTW, you need to read some of my articles about what constitutes real science. Here are the problems with that article:

      1. It was published in a very low ranked journal that has almost no reputation in the scientific world. If the researchers actually had real data, it’s so important that it should have been published one of the 500 higher ranked medical journals.
      2. The researchers failed miserably to distinguish between the excess Na+ versus the glutamate. That’s just amateurish.
      4. The amount of MSG they added would be like consuming a kg of NaCl. It’s the sodium that harms. These guys would get flunked out of a real Ph.D. program for doing this high school science fair crap.

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  • Grace Flower

    Wow, I am not a scientist..just a Mother trying to figure out what is wrong with her son. I have a 10 year old that has depression, anxiety, suicidal thoughts (that seemed to come out randomly), learning disabilities, inattentive ADD, allergies, asthma, intolerance to artificial colors and medication hypersensitivity. All of his Dr.’s call him a puzzle and I have done everything in my power to make him better. After a third anti-anxiety medication caused a full body rash, we decided to do a strict elimination diet. Fruits, vegetables, meat and dairy. After two weeks, there was no depression, he stopped talking about suicide, he was happy and he was off all medications. After seven weeks, his grades have improved, his teachers say that he’s more outgoing, smiling and making friends. His personality has changed and he is so much easier to be around, homework is not a nightly struggle, his memory is so much better. He received a flu shot at week five and by that night, he was threatening to kill us and kill himself, he was sobbing, depressed and miserable. His flu shot contained MSG. You can have all the science of people that MAY be affected but my son is one of them. We have tested several foods, fast foods and suppliments and they all have overlapping ingredients of MSG. As for the blood brain barrier, all of his symptoms are neurological and emotional. I believe the Dr.’s that say that an allergy effects an area of the body and I believe that my son’s area is the brain. Swelling in the brain could cause personality changes and neurological issues.

    • R.w. Foster

      Slight problem with your hypothesis: There’s no MSG in any vaccine.

      • lilady R.N.

        Small correction. Adenovirus vaccine, which is approved for use for military personnel contains MSG. There is no MSG in any seasonal influenza vaccine…or in any vaccine which “civilians” would receive and which are on the CD Childhood Recommended Vaccine Schedule and the CDC Adult Recommended Vaccine Schedule:

        • R.w. Foster

          Well, I feel a bit foolish. Thank you for that bit of knowledge you dropped on me, ma’am.

      • Skeptical Raptor

        And even if there were MSG cannot harm anyone. Period.

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