healthHealth and Medicine

What Is MSG? The Odd Tale Of Its Unsavory Reputation


Tom Hale

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist


Image credit: Poring Studio/

MSG is the flavor-boosting compound often said to be the secret ingredient that gives Chinese food its delectably moreish qualities. Some take a less savory view of this seasoning, arguing its supposed link to a host of unpleasant side effects known as “Chinese restaurant syndrome,” characterized by headache, nausea, numbness, and palpitations. 

In reality, MSG is safe to eat and there’s very little evidence it causes any health concerns, serious or otherwise. Any untoward symptoms people experience after consuming MSG are most likely the impact of gorging themselves on spring rolls.


In a very unexpected twist, the MSG myth can also be traced back to a bizarre mix of anti-Asian prejudice, a strange story of fake identities, and (perhaps) a prank that snowballed out of control.

What is MSG? And where does MSG come from?

MSG is short for monosodium glutamate. It takes the physical form of white crystalline flakes that dissolve into food. Chemically speaking, it’s the sodium salt of glutamic acid. It can be found naturally in the form of glutamate in foods including tomatoes, mushrooms, and some cheeses. It’s even found in breast milk.

msg crystals
MSG up close. Image Credit: PENpics Studio/

Why does MSG taste so good?

MSG is not a flavor itself, but a substance that enhances existing flavors in a dish, a bit like salt. Its prime property is bringing out the flavor of foods with the taste of “umami.”

Umami is that rich and deep meaty taste often utilized in Asian cuisines and found in foods such as soy sauce, seaweed, anchovies, miso, fish sauce, Worcestershire sauce, and Marmite. 


“MSG is often used as an enhancer for things where an umami taste would enhance the dish. Umami gives a meaty, brothy, savory flavor to food. So, you don’t add it because you want to taste MSG, just like you don’t add salt to a dish because you want to taste salt. You add them because they add an extra dimension to the dish,” Associate Professor Alex Russell, a researcher from CQUniversity in Australia with a keen interest in taste and smell perception, told IFLScience. 

“It’s particularly effective in foods where a meaty, brothy, or savoury dimension will help – so things like stock, gravy, savoury treats, etc,” continued Russell. “But MSG won’t help with foods where that dimension wouldn’t be good. So, if you added MSG to something where sweetness might be more appropriate, for example, that food won’t end up with a nicer flavor. It’s all about context,” he added.

MSG was first scientifically identified in 1908 by Kikunae Ikeda, a chemistry professor at the Tokyo Imperial University, who realized the tastiness of Kombu seaweed broth was largely down to this previously unrecognized chemical, MSG. Ikeda managed to isolate the glutamic acid from the kelp and submitted a patent for the chemical. 

The “miracle” ingredient quickly began commercial production and ended up in a host of food products, from stock cubes and soups to sauces and ramen. Even outside of Asia, you can find MSG in many widely munched food products, including Doritos and Pringles.

Why do people think MSG is bad?

A recent poll by the International Food Information Council found that four in 10 consumers in the US say they actively avoid MSG. But where did this bad reputation come from? 

Much of the controversy around MSG can be traced back to a correspondence letter by Dr Robert Ho Man Kwok published in the New England Journal of Medicine (NEJM) in 1968. The short paper explained the sensations the scientist had experienced after eating at a Chinese restaurant. Dubbed "Chinese restaurant syndrome,” he described the weakness, numbness, palpitations, and headaches he experienced around 15 to 20 minutes after starting the first dish. After excluding other ingredients widely used in Chinese cuisine, he put the blame solely on MSG.

The 1968 letter is still often reported to be the original source of MSG’s controversy, but it is less widely known that the paper may have been a hoax.

Professor Jennifer LeMesurier, a Writing and Rhetoric Professor at Colgate University, wrote about the MSG myth in a research paper in 2017 discussing how the debate about MSG was laced with racist stereotypes of Chinese people, noting the old NEJM letter. A few months later, to her surprise, she received a voicemail from a former orthopedic surgeon at Colgate University, Dr Howard Steel, who claimed he was the man behind the letter.


Dr Steel explained that his friend bet him $10 that he wouldn't be able to get published in the prestigious papers of the NEJM, joking that orthopedic surgeons were "too stupid." After a night of eating and drinking at their favorite Chinese restaurant, Dr Steel accepted the challenge and drew up the silliest letter he thought could subtly get through the editors, so the story goes. He signed the letter Ho Man Kwok, a play of words on “human crock,” as in a “crock of sh*t.” 

The story gets even stranger, though. There are now some doubts about whether Dr Steel actually faked the letter or whether he simply wanted to take credit for the chaos it caused. For one, Dr Robert Ho Man Kwok was a real scientist working in the US and his family believe he did genuinely write the letter to the NEJM. Then again, why would Dr Steel, a well-respected orthopedic surgeon, make up a story that he was the true author? Unfortunately, all of the characters in this story are now dead, so the full story may never be known. 

Regardless of who penned the now-notorious letter, it's obvious that it quickly took a grip on the public imagination. Within weeks, health authorities in the US were issuing warnings about the potential dangers of MSG, particularly targetting Chinese food manufacturers. 

"The weird thing is that the initial letter to the editor in the NEJM prompted quick attention from the public, despite the lack of any initial studies or scientific research," Professor LeMesurier told IFLScience. 


"Almost immediately, newspapers picked up on this question as definitive proof of MSG's ills and printed stories with headlines like 'Chinese Food Jinx is Identified' (Washington Post July 14, 1968)," she added.

It's not clear why the single letter published in the NEJM had such a profound impact on the media and public, but Professor LeMesurier suspects it may have resonated with racist preconceptions associated with Asian people and culture – some of which still live on today. 

"The broader anti-Asian sentiment that we've seen more in the past few years is definitely connected to suspicions of Chinese food as somehow always tainted or unsanitary. MSG is just one part of that suspicion that is grounded in racist hatred rather than any facts," explained LeMesurier.

"[It's] the same sort of suspicions about Chinese food that we see today in accusations of 'bat-eating' causing the coronavirus."

What does science say about MSG?

Plenty of scientific studies have snooped into the potential health effects of MSG, but scarcely any research has found hard evidence of a link between the flavor-enhancer and significant unsavory symptoms. 

Any side effects that have been reported after consuming MSG appear to be short-term, fleeting, and mild. They also only tend to appear when subjects are given huge amounts of the chemical without food. When consumed alongside food in reasonable quantities, there’s very little evidence of any significant symptoms. 

For instance, one study in the year 2000 collected 130 people who reported having a sensitivity to MSG, some were given a placebo while some were given the real deal. While it did find that large doses of MSG given without food elicited some mild symptoms, these responses were not seen when MSG was given with food.

Most health authorities also agree that MSG is perfectly fine to eat. The US Food and Drug Administration set up an independent inquiry into MSG in the 1990s, ultimately concluding that MSG is safe.


Despite all of this evidence (or lack thereof), MSG still has a bad reputation in many minds. Restaurants will boast their menu is "MSG-free!" and food snobs will stick their noses up at the sight of these three letters on an ingredients list. Over 50 years on, that strange letter in the NEJM and the media hysteria that followed still have a lot to answer for. 


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