A headache after takeout, a flushed face, a racing heart, a strange tingling in the neck: for more than fifty years, MSG (monosodium glutamate) has been blamed for all of them, once under the label "Chinese restaurant syndrome." Many people still check labels for it, and "no MSG" signs still hang in restaurant windows.
The research tells a more interesting story than either "MSG is poison" or "MSG sensitivity is a myth." Blinded studies, where neither the volunteers nor the researchers know who got MSG, have mostly failed to reproduce reactions at the amounts found in food. But large doses taken on an empty stomach can cause short-lived symptoms in some people. This guide covers what the evidence shows, where the line sits, and what to do if you think MSG bothers you.
The short version
- MSG is the sodium salt of glutamate, an amino acid found naturally in tomatoes, Parmesan, soy sauce and breast milk. Your body cannot tell the glutamate in MSG from the glutamate in food.
- Blinded tests rarely confirm MSG sensitivity. In the largest study, 130 people who believed they reacted to MSG were tested; reactions faded on retesting, only 2 of the 12 people in the final fasting round reacted to MSG but not placebo, and even they did not react consistently when MSG was given with food.
- Large fasting doses are different. The FDA notes that some sensitive people may get mild, short-lived symptoms such as headache, flushing or tingling after 3 grams or more of MSG without food. A typical serving of food with added MSG has less than 0.5 grams.
- It is not an allergy. No allergy antibody (IgE) mechanism has been shown, and there is no reliable test for MSG sensitivity.
- Regulators consider it safe at normal intakes. The FDA calls it "generally recognized as safe," and the international expert committee JECFA set no numeric limit. Europe's EFSA set a more cautious daily limit in 2017.
- No supplement has good evidence for MSG reactions. A vitamin B6 study from 1984 and a probiotic study from 2015 were small, and we found no replication of either.
What is MSG, and how is it made?
Glutamate is one of the most common amino acids in food and in the body. In 1908, the Japanese chemist Kikunae Ikeda extracted it from a seaweed broth and showed that it carried the broth's savory taste, which he named umami. He patented a way to make its sodium salt, monosodium glutamate, and commercial production began the next year.
Today MSG is made by fermenting starch, sugar beets, sugar cane or molasses, a process the FDA compares to making yogurt, vinegar or wine. Chemically, it is glutamic acid paired with sodium. Once it dissolves, the glutamate is identical to the glutamate released when your gut digests protein. The FDA estimates that an average adult gets about 13 grams of glutamate a day from protein in food, compared with roughly 0.55 grams a day from added MSG.
Most glutamate you eat never reaches the rest of the body. In animal tracer studies, the gut wall broke down about 95 percent of dietary glutamate during absorption, much of it burned as fuel, and human studies point the same way. With a meal, blood glutamate barely moves: in one study of 10 healthy men, MSG added to ordinary meals at about 7 grams a day had no clear effect on daily blood glutamate patterns. Large doses on an empty stomach are another matter; in one study of fasting men, 12.7 grams raised blood glutamate about 11-fold, while a high-protein meal did not raise it. That difference, food versus fasting, runs through the whole evidence base.
MSG has nothing to do with gluten, despite the similar name. As the FDA points out, someone with celiac disease may react to wheat in soy sauce, but not to the MSG in it.
How "Chinese restaurant syndrome" started
In 1968, the New England Journal of Medicine published a letter from Dr. Robert Ho Man Kwok describing numbness at the back of the head spreading to the arms and back, weakness and palpitations after meals at Chinese restaurants. He floated MSG as one possible cause. The letter ran under the title "Chinese-restaurant syndrome," a flood of follow-up letters arrived, and the name stuck.
Two 1969 papers in Science gave the idea momentum. One reported that MSG "is the cause" of the syndrome, from dosing experiments run before properly blinded testing became the norm. The other found that injecting MSG under the skin of newborn mice damaged their brains and made them obese as adults. That injection model is still used to create obese lab rodents today, which is why "MSG causes obesity" headlines often trace back to animals that never ate it. Injection bypasses the gut, and safety reviews note that blood glutamate levels linked to brain damage in newborn mice have not been seen in humans, even after 10-gram doses in water.
A survey a decade later showed how loose the link was. In a 1979 survey of 3,222 people, 43 percent connected unpleasant symptoms with certain foods or eating situations, but only 1 to 2 percent described the classic syndrome, and only 0.19 percent linked it to Chinese food.
The old name was later dropped. In 1995, the FDA's scientific advisers at the Federation of American Societies for Experimental Biology (FASEB) used "MSG symptom complex" instead, and in 2020, according to news reports, Merriam-Webster added a note to its entry for the old term calling it dated and offensive, after a campaign run by the MSG maker Ajinomoto. The old name also singled out one cuisine, even though MSG is used in many packaged foods and glutamate is naturally rich in staples such as Parmesan and tomatoes. This guide uses "MSG symptom complex" except when describing the history.
Is MSG sensitivity real? The blinded studies
The fair test is a double-blind, placebo-controlled challenge: volunteers drink or swallow MSG on one day and a look-alike placebo on another, without anyone in the room knowing which is which. Here are the key studies:
| Study | Who and how much | What happened |
|---|---|---|
| Geha, 2000 (largest, multicenter) | 130 people who believed they reacted to MSG; 5 g without food | 50 reacted to MSG only, 17 to placebo only, 19 to both. On a second round, only 19 again reacted to MSG but not placebo; of 12 of them retested twice more, 2 reacted to MSG each time, and with food each reacted to only 1 of 3 MSG challenges. |
| Yang, 1997 | 61 people who believed they reacted to MSG; up to 5 g, fasting | 36 percent reacted to MSG only vs 25 percent to placebo only (10 percent to both), not a significant difference. Symptoms were more severe after MSG, and headache, numbness, flushing and muscle tightness were more frequent. Apparent threshold: 2.5 g. |
| Tarasoff, 1993 | 71 healthy adults; 1.5 to 3.15 g before a standard breakfast, over 5 days | 85 percent had no symptoms on MSG and 86 percent none on placebo. |
| Prawirohardjono, 2000 | 52 healthy adults; 1.5 and 3 g with breakfast | Symptoms did not differ from placebo. |
| Wilkin, 1986 (blinding not reported in the abstract) | 24 people tested for flushing, 18 with a history of it after Chinese meals | No flushing was provoked. |
Gram amounts are MSG. For scale, 5 g is about 71 mg per kg of body weight for a 70 kg (154 lb) adult, and a typical serving with added MSG contains under 0.5 g.
Two things stand out. First, placebo reactions are common: in the largest study, 36 of 130 people (28 percent) reacted to the placebo. Expectation is powerful, and a 2026 systematic review highlighted "the influence of psychological expectation on reported outcomes." Second, blinding MSG is hard because it has a distinctive taste. A 2016 review judged that many "blind" studies giving MSG as a strong solution (more than 2 percent) were probably not properly blinded, because MSG is easy to taste at that strength.
That still leaves a real, narrow effect. The 1995 FASEB report concluded there is a subgroup of otherwise healthy people "who may respond to large doses (> 3 g)" under specific conditions, mainly on an empty stomach. Reviews since then agree: symptoms are rarely confirmed at realistic doses with food, and they show up mostly in high-dose, fasting challenges. In PubMed searches through November 2026, we found no double-blind MSG-versus-placebo challenge in people who believe they react to MSG that is newer than the studies in the table.
MSG sensitivity symptoms, allergy and look-alikes
The symptoms listed in the FASEB report are short-lived and usually mild: headache, numbness or burning at the back of the neck spreading to the arms and back, tingling or warmth in the face, facial pressure or tightness, chest pain, flushing, palpitations, nausea, drowsiness and weakness. In the largest challenge study, reactions counted only if they began within 2 hours, and other challenge studies followed people for hours (up to about 12 hours in one asthma study), not days; we found no controlled data for the "48 to 72 hour" durations sometimes quoted online.
MSG sensitivity is not an allergy. The 1997 challenge study found that the symptom pattern does "not support an IgE-mediated mechanism," and there is no validated skin, blood or at-home test for it. Meanwhile, a restaurant meal contains many other possible triggers:
| Suspect | Why it can look like an MSG reaction |
|---|---|
| Histamine | Soy sauce, fish sauce, aged and fermented foods can carry histamine. A 1989 NIH analysis found 2,392 micrograms per gram in one tamari sample, and noted that histamine toxicity resembles the classic syndrome. See our histamine intolerance guide. |
| Food allergens | Peanuts, tree nuts, shellfish, fish, sesame, soy, wheat and egg are common in many cuisines and can cause true allergic reactions. |
| Alcohol and sulfites | Alcohol is a recognized headache trigger, and sulfites (in wine, dried fruit and some sauces) are an established additive trigger for asthma (see our sulfite sensitivity guide). |
| Salt and a large meal | Thirst, bloating and sluggishness after a big, salty meal are expected, with or without MSG. |
| Something else entirely | Recurrent flushing, palpitations and headaches that are not tied to meals need a medical check; doctors have reported a hormone-secreting adrenal tumor that first looked like a prolonged attack of the syndrome. |
Gut symptoms after takeout also have common dietary causes, such as hard-to-digest carbohydrates called FODMAPs (in onion, garlic and wheat) or lactose in creamy dishes; see our low-FODMAP guide.
Does MSG cause headaches or migraines?
Headache is the most commonly reported MSG symptom, and here the evidence is genuinely mixed. A 2016 systematic review of the controlled studies found that in six studies where MSG was eaten with food, headache was no more frequent than with placebo, except in women in one study (3 g in beef broth). In seven studies where MSG was given without food, four found more headaches. The authors called the evidence inconclusive because of poor blinding and inconsistent results, and the first author was employed by an MSG manufacturer when the review was published.
The clearest positive results come from a Danish research group that gave healthy volunteers MSG dissolved in sugar-free soda on an empty stomach. In one 2013 study, 150 mg per kg of body weight (about 10.5 grams for a 70 kg adult) daily for five days caused headache in 8 of 14 people, against 2 of 14 on placebo, and raised blood pressure. That is roughly 20 times the MSG in a typical serving, taken all at once in a drink. The authors also reported that most volunteers correctly guessed what they had been given, so the study could not be considered truly blind.
Headache specialists take these provocation studies seriously. A 2016 review in the journal Headache concluded that caffeine withdrawal and "MSG (dissolved in liquid)" have the strongest evidence among dietary triggers. MSG was listed as a headache cause in the 2013 beta (trial) version of the International Classification of Headache Disorders, the diagnostic manual headache specialists use, but we did not find it in the online outline of the current version. The honest summary: large doses in liquid on an empty stomach can bring on headaches in some people, while the amounts in normal meals have not been shown to. For what the research shows on supplements and migraine, see our guide to supplements for migraines.
MSG and asthma
A small 1987 study reported that 13 of 32 people with asthma reacted to MSG, but the test was single-blind, and later reviewers noted that positive studies like it were done after stopping essential asthma medicines. Later studies have not confirmed it. In a single-blind screening study, researchers at Scripps gave 2.5 grams of MSG to 100 people with asthma, 30 of whom reported attacks after restaurant meals, and none developed a significant drop in lung function or asthma symptoms. A Cochrane review found only two eligible trials (24 adults, no children) and no difference between MSG and placebo; it concluded there is no evidence to support avoiding MSG in chronic asthma, while noting the data are limited.
If you have asthma, do not stop controller medicines to test a food. Sulfites and aspirin, not MSG, are the well-established chemical asthma triggers.
Is MSG bad for you? Safety limits, weight and the brain
Regulators broadly agree that MSG is safe at the amounts people eat, while differing on how cautious to be:
- FDA (US): MSG is "generally recognized as safe." The agency says it has received reports of headache and nausea after MSG-containing foods, but "we were never able to confirm that the MSG caused the reported effects."
- JECFA (World Health Organization and FAO expert committee): in its 1987 evaluation, it set an acceptable daily intake (the amount considered safe to eat every day for life) of "not specified," its most favorable category, meaning no numeric limit was considered necessary.
- EFSA (European Union): in 2017 it set a group acceptable daily intake of 30 mg per kg of body weight per day for added glutamates (about 2.1 grams of glutamic acid for a 70 kg adult). The limit comes from a rodent study with a standard 100-fold safety margin. EFSA noted that it sits below the doses linked to symptoms in humans (above 42.9 mg per kg for the symptom complex, 85.8 mg per kg for headache and 150 mg per kg for a blood pressure rise). Its intake estimates exceeded the limit in several age groups (on average in toddlers and children, and at high intakes in every age group), mostly through fine bakery wares and soups and broths, though EFSA judged that these estimates were probably too high.
For perspective, a breastfed baby takes in about 36 mg of free glutamate per kg of body weight a day from breast milk, according to a German food safety commission, which is already above EFSA's added-glutamate limit.
Weight: some Chinese population studies linked higher MSG use to being overweight; in one following 10,095 adults for about five and a half years, the top fifth of MSG users had a 33 percent higher risk of becoming overweight than the bottom fifth. Another Chinese cohort of 1,282 adults found no link between MSG intake and weight gain over five years, and the authors concluded that no association exists once other foods and diet patterns are accounted for. These are observational studies, which track what people already eat rather than assigning MSG, so they cannot show cause, and feeding trials have not shown a consistent effect of MSG on how much people eat.
Blood pressure: very large fasting doses raised blood pressure in the Danish studies, and one Chinese cohort linked MSG intake to rising blood pressure over five years. A large four-country study, by contrast, found that people who ate more glutamic acid from protein had slightly lower blood pressure.
The brain: glutamate is a brain messenger, which fuels worries about "excitotoxins." But the blood-brain barrier, a tightly sealed lining of the brain's blood vessels, keeps blood glutamate out of most of the brain, even at high blood levels.
Natural glutamate in foods and "No MSG" labels
Free glutamate, the kind that tastes savory, occurs naturally in many foods. Aged and fermented foods such as Parmesan and soy sauce are among the richest:
| Food | Free glutamate (mg per 100 g) |
|---|---|
| Parmesan cheese | about 1,200 |
| Soy sauce | 400 to 1,300 |
| Peas | 200 |
| Potatoes | 180 |
| Tomatoes | 140 |
| Beef | 33 |
| Human breast milk | 22 |
| Cow's milk | 2 |
Typical values compiled by Food Standards Australia New Zealand (2003), as tabled by the German Research Foundation's food safety commission (2005). Mushrooms, corn and asparagus also contain free glutamate.
The recommended level for MSG as an additive is 0.1 to 0.8 percent of a food's weight, roughly the free glutamate level of a tomato or Parmesan. Under FDA rules, added MSG must appear in the ingredient list as "monosodium glutamate" and cannot be hidden under "spices and flavoring." Foods with ingredients that naturally contain free glutamate, such as hydrolyzed vegetable protein, autolyzed or hydrolyzed yeast, yeast extract, soy extracts and protein isolate, cannot claim "No MSG" or "No added MSG," but they do not have to say they contain glutamate. So "no MSG" does not mean "no glutamate," and Parmesan, at about 1.2 percent free glutamate, has more free glutamate by weight than a food made with MSG at the recommended levels.
MSG vs salt: the sodium question
MSG contains sodium, but less than table salt: about 12 grams of sodium per 100 grams, compared with about 39 grams for salt. Because MSG boosts savory flavor, swapping some of the salt in a recipe for a smaller amount of MSG can cut sodium. In one example, replacing half a teaspoon of salt (2.5 grams) with half a teaspoon of MSG (2.0 grams) in a 500-gram recipe reduced its sodium by about 37 percent, and in a taste-panel study, adding 0.7 percent MSG to spicy soups allowed a 32.5 percent sodium reduction.
Keep the claim modest. Most estimates of population-wide sodium savings are computer models, many funded by or co-authored with MSG makers, and a 2023 scoping review by the Academy of Nutrition and Dietetics' Evidence Analysis Center found only one study that measured an umami seasoning's effect on people's total daily sodium intake. We found no trial showing that cooking with MSG lowers blood pressure. MSG used instead of some salt can help; MSG added on top of the usual salt just adds sodium. For other ways to cut sodium, see our article on salt substitutes and the sodium ingredient page.
Vitamin B6, probiotics and glutamine
Vitamin B6. Some websites suggest vitamin B6 for MSG reactions. The idea comes from one lab in the early 1980s. In a 1984 study, researchers screened 155 students, picked 27 with signs of low B6 status, and found 12 who reacted to a glutamate challenge. After 12 weeks of double-blind treatment, 8 of the 9 given B6 no longer reacted, while all 3 given placebo still did. That is a tiny study of people chosen for low B6, and we found no replication in PubMed through November 2026. B6 is safe at normal doses, but long-term high doses can damage nerves, so stay under the upper limit (see our guide to supplement upper limits).
Probiotics. One 2015 crossover study gave 30 young Korean adults who believed they were MSG-sensitive the probiotic Lactobacillus brevis G101 for five days in one week and a placebo in the other, with each week ending in a meal containing 6 grams of MSG. Symptom scores were somewhat lower after the probiotic. But one author worked for the company that made the probiotic capsules, there was no MSG-free meal to show that MSG caused the symptoms, and we found no replication of the result. We found no other supplement with published human trials for MSG reactions.
Glutamine and glutamic acid supplements are not MSG. L-glutamine is a different amino acid, popular for gut and workout support (see our L-glutamine for gut health review). A glutamic acid supplement does provide glutamate, typically a few hundred milligrams, which is small next to the roughly 13 grams a day from food protein. We found no studies testing either supplement in people who report MSG sensitivity. If a product seems to bother you, stopping it is reasonable.
If you think MSG bothers you
- Keep a simple diary of what you ate and drank (including alcohol), roughly how much, whether it was a full meal or a snack on an empty stomach, and when symptoms started. Patterns often point to something other than MSG.
- Eat MSG-containing foods with a meal, not on an empty stomach. The controlled studies are most reassuring for normal amounts eaten with food.
- Read labels for "monosodium glutamate" if you prefer to limit it, while knowing that natural glutamate in foods such as Parmesan and tomatoes is the same molecule.
- Do not try a fasting, multi-gram MSG "challenge" at home. If you want to test yourself, compare a normal meal with and without a small, known amount of MSG, and if you can, have someone else prepare both versions so you do not know which is which, since knowing what you ate can shape how you feel.
- See a doctor or allergist for severe, recurrent or unexplained reactions, especially if you might have a true food allergy.
- Emergency: swelling of the lips, tongue or throat, wheezing, trouble breathing, spreading hives or fainting after eating. Use epinephrine if prescribed and call emergency services. A severe reaction after a restaurant meal needs a proper allergy work-up, whatever you suspect.
- Urgent care: chest pain, or a racing or irregular heartbeat that does not settle within a few minutes.
- See a doctor for repeated flushing, palpitations or headaches, especially if they happen without food.
- Asthma: never stop controller medicines to test a food.
Frequently asked questions
Is MSG sensitivity real?
Yes, but only in a narrow sense. Some people get short-lived, mild symptoms such as headache, flushing or tingling after large doses of MSG, usually 3 grams or more on an empty stomach. At the amounts in a normal meal, double-blind studies have rarely been able to tell MSG from a placebo, and in the largest study, which began with 130 people who believed they reacted, only 2 of the 12 put through a final round of repeat testing reacted to MSG but not placebo, and even their symptoms were not consistent.
Why is it called "Chinese restaurant syndrome"?
The name comes from a 1968 letter in the New England Journal of Medicine describing numbness, weakness and palpitations after meals at Chinese restaurants, which suggested MSG as one possible cause. The label stuck, even though MSG is used in many packaged foods and glutamate is naturally rich in foods such as Parmesan and tomatoes. Researchers now use the term "MSG symptom complex," and according to news reports, Merriam-Webster added a note in 2020 calling the old term dated and offensive.
Is MSG sensitivity an allergy? Is there a test?
No. Reactions to MSG have not been shown to involve the allergy antibody IgE, and there is no validated skin, blood or at-home test for MSG sensitivity. A severe reaction after a meal, such as throat swelling or trouble breathing, points to a true food allergy or another cause and needs urgent medical care and an allergy work-up.
Is MSG bad for you?
For most people, no. The FDA classifies MSG as generally recognized as safe, and JECFA, the WHO and FAO expert committee, set no numeric daily limit. Europe's EFSA set a more cautious limit in 2017, equal to about 2.1 grams of glutamic acid a day from added glutamates for a 70 kg adult; its intake estimates exceeded that limit in some age groups, though EFSA judged the estimates probably too high. Large doses on an empty stomach can cause short-lived symptoms in some people, and the links to weight gain and to blood pressure over time come from observational studies that cannot show cause.
How much MSG causes symptoms?
The FDA's scientific advisers concluded that mild, short-lived symptoms may occur in some sensitive people after 3 grams or more of MSG without food. A typical serving of food with added MSG contains less than 0.5 grams, and the average US adult gets about 0.55 grams a day from added MSG, compared with about 13 grams of glutamate from food protein.
How long do MSG symptoms last?
The FDA's scientific advisers described the symptoms as short-lived and usually mild. The largest challenge study counted reactions only if they began within 2 hours, and in one small asthma study, reactions began 6 to 12 hours after MSG. We found no controlled data for the 48 to 72 hour durations sometimes quoted online. Symptoms that last for days or keep coming back are worth raising with a doctor.
Does MSG cause headaches or migraines?
Large doses can in some people. Studies giving healthy volunteers about 5 to 10 grams of MSG dissolved in a drink on an empty stomach found more headaches than with placebo. When MSG was eaten with food, a 2016 systematic review found no consistent difference, apart from one subgroup of women. MSG is a commonly reported migraine trigger, but normal amounts in meals have not been shown to cause headaches. See our guide to supplements for migraines.
MSG vs salt: how much sodium does MSG contain?
MSG contains about 12 grams of sodium per 100 grams, roughly a third of table salt's 39 grams. Using a little MSG instead of some salt can cut a recipe's sodium, but adding MSG on top of the usual salt only adds sodium, and we found no trial showing that cooking with MSG lowers blood pressure.
Which foods naturally contain glutamate?
Parmesan cheese (about 1,200 mg of free glutamate per 100 g), soy sauce, tomatoes, peas, potatoes, mushrooms and human breast milk all contain free glutamate. It is the same molecule as the glutamate in MSG, and your body handles both the same way.
Does "No MSG" on a label mean a food has no glutamate?
No. In the US, added MSG must be listed as monosodium glutamate, and foods with ingredients that naturally contain free glutamate, such as hydrolyzed vegetable protein, yeast extract or soy extracts, are not allowed to claim "No MSG" or "No added MSG." But those foods do not have to say they contain glutamate, and many whole foods, like tomatoes and Parmesan, are naturally rich in it.
Can vitamin B6 or another supplement help with MSG reactions?
There is no good evidence. A 1984 study in 12 people selected for low vitamin B6 status reported fewer reactions after B6, and a 2015 study of 30 young adults tested a probiotic, but we found no replication of either. Glutamine supplements are a different amino acid, not MSG. Stay under the vitamin B6 upper limit, since long-term high doses can damage nerves.
The bottom line
MSG sensitivity is real in a narrow sense: some people get short-lived, mild symptoms such as headache or flushing after large doses of MSG, usually 3 grams or more on an empty stomach. At the amounts in a normal meal, blinded studies have rarely been able to tell MSG from placebo, and many reactions blamed on MSG likely come from expectation or from other parts of the meal, such as alcohol, histamine, allergens or simply a big, salty dinner.
MSG sensitivity is not an allergy and has no reliable test, and MSG itself is considered safe by the FDA and JECFA, with Europe's EFSA taking a more cautious line on very high intakes. If you feel better avoiding it, labels make that easy, but there is no need to fear tomatoes, Parmesan or a bowl of soup. No supplement has good evidence for MSG reactions.