What is an MSG-Induced Headache?

You may have heard the Chinese restaurant syndrome—a constellation of symptoms (most notably a headache) that people sometimes experience after eating Chinese restaurant food.

While this syndrome has been linked to the MSG content of Chinese food, scientists have not been able to prove this precise connection. Regardless, many people commonly report MSG as a headache or migraine trigger.

MSG stands for monosodium glumtamate and is the sodium salt of an amino acid found naturally in our bodies called glutamic acid. While MSG is found naturally in foods, like tomatoes and cheeses, it can also be produced through the fermentation of starch, sugar, or molasses, and added to foods.

According to the US Food and Drug Administrations, MSG is "generally recognized as safe," to consume when added to foods. Foods that commonly contain added MSG are processed or packaged foods.

Most people with an MSG-induced headache describe a tightening or even burning head sensation. People will also commonly notice muscle tenderness around their skull. In people with a history of migraines, MSG triggers a migraine—in this instance, people usually report a classic throbbing or pulsating headache.

An MSG-induced headache develops within 1 hour of consuming MSG and resolves within 72 hours of MSG consumption. Also, an MSG-induced headache has at least one of the following five characteristics:

• Bilateral (i.e., both sides of the head)
• Mild to moderate intensity
• Pulsating quality (i.e., throbbing)—like a migraine
• associated with a number of other symptoms that include: facial flushing, chest and face pressure, burning feeling in the neck, shoulder, and/or chest, dizziness, and stomach discomfort.
• aggravated by physical activity

One study in Cephalalgia found that people who consumed a high amount of MSG—like a sugar free soda containing 150mg/kg of MSG—had an increase in their blood pressure, although this was temporary. Chronic daily intake of high doses of MSG may also cause fatigue.

Scientists are not completely certain on the mechanism behind MSG-induced headaches. It's likely that the glutamate part of MSG activates receptors called NMDA receptors. This activation leads to the release of nitric oxide, which then leads to the dilation or widening of blood vessels around the skull.

If you suspect MSG is a headache or migraine trigger for you, avoiding it is probably your best bet, regardless of what the science says—this is a good example of tailoring your individual diet to your unique migraine or headache triggers.

In addition, research has shown that developing a tolerance for MSG is unlikely—so you are not likely to beat out your MSG-sensitivity. Instead, scope out the nutritional content of all the foods you consume. If you are MSG-sensitive, double check to make sure there is no added MSG, and then enjoy. If there is added MSG, choose another option, a healthy one too if possible.