MSG (Monosodium Glutamate)
Last reviewed October 18, 2026 · Evidence strength: Moderate · How we grade evidence
In plain words: MSG is one of the most studied food ingredients. In blinded tests, people who believe they react to it usually can't tell it apart from a placebo when it's eaten with food. The glutamate in MSG is the same as the glutamate in tomatoes, cheese and broth. A few people may notice mild, short-lived symptoms after a large amount on an empty stomach, but there's no good evidence it causes obesity or brain damage at normal amounts.
Also listed on labels as: Monosodium glutamate, MSG, E621, Glutamate
What is it, and why is it in food?
MSG is the sodium salt of glutamate, an amino acid that gives savory "umami" flavor. It's made by fermentation. It's in chips and snacks, seasoning mixes, soups, frozen meals and restaurant food. Glutamate also occurs naturally in parmesan, tomatoes, mushrooms and soy sauce.
What does the science say?
| The popular claim | "MSG is an excitotoxin causing headaches, obesity and metabolic damage; it should best be avoided." (Dr. Eric Berg) |
| Our verdict on that claim | Contradicted |
| Evidence strength | Moderate: double-blind challenge studies and regulatory reviews. |
| Kinds of studies | Double-blind placebo-controlled challenge studies, systematic review, EU and FDA reviews |
- Reactions: In a multicenter double-blind study of 130 people who said they react to MSG, responses were inconsistent, couldn't be reproduced, and didn't happen when MSG was eaten with food.1
- Headaches: A systematic review of human studies didn't find consistent evidence that MSG causes headaches, though it called for more studies. (The lead author works with a glutamate industry group.)2
- Obesity and brain damage: These findings come from rodents given injections or very high doses.
What do regulators say?
- FDA: GRAS. Added MSG must be listed on the label. FDA notes that a few sensitive people may get mild, short-lived symptoms after 3 g or more without food. Typical added-MSG intake is about 0.55 g a day, versus about 13 g of glutamate from protein foods.3
- EFSA (2017) set a group safe daily limit of 30 mg per kg of body weight and noted some high consumers exceed it.4
Who should be careful?
- People who notice symptoms after large amounts on an empty stomach can simply limit it.
How common is it in US foods?
In our check of USDA's Branded Foods database, 11,071 of 438,129 US packaged foods with an ingredient list name MSG (monosodium glutamate) (about 2.5%, or roughly 1 in 40).5 It shows up most often in: chips, pretzels & snacks (1,952); other snacks (1,563); seasoning mixes, salts, marinades & tenderizers (887); sausages, hotdogs & brats (581); salad dressing & mayonnaise (489). These are label records companies sent to USDA, mostly in 2021 to 2023, so some products have changed since. Counts come from a text match of ingredient lists and are approximate.
Swaps and tips for families
- No swap needed for safety.
- Seasoning mixes, chips and instant soups are the main sources if you'd still like to cut back.
Beyond the plate: related non-food exposures
None.
Frequently asked questions
Is MSG bad for you?
No good evidence says so at normal amounts. Blinded studies don't reproduce reactions when MSG is eaten with food.
Is MSG an excitotoxin?
The brain-damage findings come from rodents given injections or very high doses, not from people eating normal amounts.
Can MSG be hidden in food?
Added MSG must be listed on US labels. Ingredients like yeast extract are listed by name, but the label doesn't have to say they contain glutamate.
Does MSG cause headaches?
Studies haven't found a consistent link. A few people may get mild, short-lived symptoms after large doses on an empty stomach.
Related guides
Sources
Every source below was checked against PubMed, the publisher or the official page by our research team in October 2026.
- Review of alleged reaction to monosodium glutamate and outcome of a multicenter double-blind placebo-controlled study. The Journal of nutrition, 2000. PubMed 10736382 · doi:10.1093/jn/130.4.1058S
- Does monosodium glutamate really cause headache? : a systematic review of human studies. The journal of headache and pain, 2016. PubMed 27189588 · doi:10.1186/s10194-016-0639-4
- FDA Q&A on MSG. Link
- Re-evaluation of glutamic acid and glutamates (E 620-625) as food additives. EFSA J, 2017. PubMed 32625571 · doi:10.2903/j.efsa.2017.4910
- FoodData Central, Branded Foods dataset (release 2026-04-30). U.S. Department of Agriculture, Agricultural Research Service, 2026. Link
This guide is for general education. It is not medical advice and does not replace advice from your doctor, pediatrician, allergist or registered dietitian. If you think you or your child reacted to a food, talk to a health professional. Research changes; we review these pages when new evidence or rules come out. Last reviewed October 18, 2026. Spotted an error? Email [email protected].