Monosodium glutamate doesn’t cause side effects because it isn’t a medical treatment, but this common food additive appears to trigger adverse reactions such as headaches, nausea and facial tightness in certain people, according to Mayo Clinic. As of 2015, researchers haven’t reported conclusive evidence that MSG indisputably causes these reactions.
Reactions linked to MSG are collectively known as MSG symptom complex, as Mayo Clinic explains. Other reported reactions include sweating, weakness, heart palpitations and chest pain. Some individuals develop a flushed appearance and feel tingling, numbness or burning sensations around the face or neck. These mild reactions are short-term and don’t require treatment.
MSG is a naturally occurring sodium compound that comes from glutamic acid, as the U.S. Food and Drug Administration explains. The compound is already present in many foods, including cheese and tomatoes, but MSG is also fermented from food products such as sugar cane and starch and used as a flavor enhancer.
On average, adults consume about 13 grams of naturally occurring glutamate daily, while they consume about 0.55 grams of added MSG each day, according to the U.S. Food and Drug Administration. However, both compounds undergo the same metabolic process in the body. Under regulations, the FDA categorizes MSG with substances it rates as generally recognized as safe, or GRAS, because experimental trials haven’t produced any consistent results of allergic reactions. Since sensitive individuals must avoid consuming the compound, food manufacturers are required to label foods containing added MSG.