Definition

MSG symptom complex is a set of symptoms associated with eating food with the additive monosodium glutamate (MSG). MSG is the sodium salt a common amino acid, glutamic acid. MSG is found naturally in our bodies and in many foods including cheese and tomatoes. MSG is added to many different types of foods as a flavor enhancer.

Alternative Names

Hot dog headache; Glutamate-induced asthma; MSG (monosodium glutamate) syndrome; Chinese restaurant syndrome; Kwok's syndrome

Causes

Reports of reactions to MSG originated in 1968 in a letter published in the New England Journal of Medicine. Since then, reports of reactions to MSG have come from people claiming to experience symptoms after consuming food containing MSG. However, studies on MSG in foods have failed to find a conclusive link between MSG and the symptoms some people describe.

The US Food and Drug Administration (FDA) did a study of the issue and found no evidence that MSG in food caused symptoms. The report did find minor reactions in people who consumed 3 or more grams of MSG alone without food. Most foods with MSG have less than 0.5 grams of the additive.

MSG is rated as "generally considered safe" by the FDA.

Symptoms

Symptoms, if they occur, are usually mild and go away in a short time:

• Flushing
• Headache
• Muscle aches
• Numbness or burning in or around the mouth
• Heart palpitations
• Tingling
• Drowsiness

Exams and Tests

There are no tests for MSG symptom complex.

Treatment

Most symptoms are mild, such as headache or flushing, and need no treatment.

Outlook (Prognosis)

Most people recover from perceived MSG symptom complex without treatment and have no lasting problems.

When to Contact a Medical Professional

Get emergency medical help right away if you have signs of a possible allergic reaction:

• Chest pain
• Heart palpitations
• Shortness of breath
• Swelling of the lips or throat

References

Aronson JK. Monosodium glutamate. In: Aronson JK, ed. Meyler's Side Effects of Drugs. 16th ed. Waltham, MA: Elsevier; 2016:1103-1104.

Bush RK, Baumert JL, Taylor SL. Reactions to food and drug additives. In: Burks AW, Holgate ST, O'Hehir RE, et al. eds. Middleton's Allergy: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 80.

US Food and Drug Administration website. Questions and answers on monosodium glutamate. www.fda.gov/food/food-additives-petitions/questions-and-answers-monosodium-glutamate-msg. Accessed May 18, 2022.