Few ingredients inspire as much fear as MSG, or monosodium glutamate. While an overtly chemical name and a similarity in appearance to salt certainly don’t help its case, the food additive is especially reviled because some people believe that consuming it causes a slew of symptoms, from headache to palpitations to numbness.
But is MSG actually bad for you? Monosodium glutamate has a terrible rap due to decades of anecdotal reports and xenophobia—but it’s probably nowhere near as detrimental to your health as you think. Here’s everything you need to know about the misunderstood ingredient, according to experts.
What is MSG?
Monosodium glutamate is a food additive that enhances the savory flavor in food. In technical terms, MSG is the sodium salt of the common amino acid glutamic acid, per the Food and Drug Administration (FDA). It takes the form of a white, crystalline powder. Importantly, MSG tastes really good—it can deepen flavor and make food taste more like itself, much like salt does.
You can find MSG at almost any supermarket in America, but it’s far more popular in Eastern Asia. The ingredient was first discovered by Japanese chemist and professor Kikunae Ikeda, who extracted it from dashi broth in 1908 and almost immediately began selling it, the FDA explains.
MSG is a completely natural substance. It occurs in foods like ripe tomatoes, aged cheeses, fish, mushrooms and seaweed—all of which share that deep, earthy, savory flavor. Today, MSG is produced by fermenting starch, sugar beets, sugar cane, or molasses, the FDA says. And despite the name, it contains no gluten. It is “generally recognized as safe” by the FDA.
Is MSG bad for you?
“There is no good research to back up the notion that MSG is bad for you,” explains Susan Levin, M.S., R.D., C.S.S.D., director of nutrition education at Physicians Committee for Responsible Medicine. “In fact, international organizations such as the World Health Organization, the Food and Drug Administration, and the European Food Safety Association classify MSG as ‘generally recognized as safe.’”
“Over the years, FDA has received reports of symptoms such as headache and nausea after eating foods containing MSG,” the agency explains. “However, we were never able to confirm that the MSG caused the reported effects.”
One FDA-commissioned report identified a few “short-term, transient, and generally mild symptoms” of consuming MSG, including headache, numbness, flushing, tingling, palpitations, and drowsiness, but only in sensitive individuals who consume 3 grams or more of MSG without food—an unlikely scenario.
Another 2019 review concluded that many of the reported negative side effects of MSG are “poorly informative, as they are based on excessive dosing that does not meet with levels normally consumed in food products.”
The ingredient might also increase meal satisfaction, even with less food. A small 2014 study divided people into two groups: one received soup with MSG, while the other had plain soup. When the two groups later consumed lunch, the MSG group ate significantly less than the non-MSG group, but reported feeling just as satisfied by their food. This suggests that MSG might even help you feel fuller, aiding in weight-loss journies, although there’s no definitive link yet.
But if you always feel gross after eating foods high in MSG, you don’t have to feel bad about cutting it out of your diet: “One will hear plenty of stories of less-than-desirable reactions to MSG,” Levin explains. “If you are one of those people, it hardly matters what the research shows. You probably want to avoid an ingredient that doesn’t make you feel well.”
Why does MSG have a bad reputation?
Despite the prevalence of MSG (and its flavor-enhancing power) Western culture largely understands the additive as unhealthy. Much of that stigma can be traced back to a letter to the editor published in The New England Journal of Medicine in 1968, in which a doctor described “a strange syndrome whenever I have eaten out in a Chinese restaurant.” That mysterious illness included numbness, weakness, and heart palpitations—and he mused that cooking wine, MSG, or too much salt could be the culprit.
Although the letter included no actual research, it stuck: The public pinned the blame on MSG, and the term “Chinese Restaurant Syndrome” entered the popular lexicon. Combining a fear of food additives and a long history of anti-Asian xenophobia in the United States, this so-called syndrome turned monosodium glutamate into a bogeyman.
In the ensuing years, flawed studies and inflammatory reports only reinforced the idea that MSG could make you sick, per FiveThirtyEight. Now, restaurants will proudly announce that they don’t use MSG in their kitchens. And brands like Frito-Lay advertise that their products contain no added MSG, too.