MSG is considered safe by the FDA but has been blamed for headaches, flushing and difficulty breathing. Here's what the science says.
Kung Pao Broccoli

Pictured recipe: Kung Pao Broccoli

What Is MSG?

Monosodium glutamate (MSG) is a flavor enhancer used in savory foods, especially Asian foods. It contains sodium, but only a third of the amount that you'd get from the same amount of salt. In fact, a recent study published in the journal Nutrients, researchers found that replacing table salt with MSG may reduce sodium intake. That's in addition to the Food and Drug Administration's (FDA) declaration that MSG is generally recognized as safe.

MSG also includes glutamic acid (aka glutamate), an amino acid that occurs naturally in foods like tomatoes, mushrooms, parmesan cheese, and soy sauce and is the source of our fifth taste-umami.

We eat about 13 grams of natural glutamate a day on average, compared to only around half a gram from MSG. However, MSG is used in processed foods, so if you're eating food that's packaged, your consumption of MSG might be higher than if you're cooking from scratch.

Is MSG Bad for You?

Some people say they are sensitive to MSG or have reactions to MSG–that MSG gives them headaches, worsens their asthma, causes chest pain or heart palpitations, or causes mild mood changes or other symptoms–MSG side effects. Those were once collectively referred to as Chinese Restaurant Syndrome because initial research pointed the finger at Chinese food as the main source of MSG in the 1960s. That led to people avoiding MSG to the point that Chinese restaurants would print "No MSG" on menus in order to attract customers. Today, it's referred to MSG symptom complex.

Contrary to popular belief, decades of research fails to support the link between MSG and these reported side effects.

A modest amount of added MSG found in the typical Western diet is not linked to symptoms of Chinese Restaurant Syndrome, according to scientific literature from the 1970s to today.

No adverse symptoms were observed when people consumed MSG as part of a meal-even at high doses (up to 147 grams/day), according to a review of studies, published in 2000 in the Journal of Nutrition.

There's one caveat though: eating large doses of MSG may lead to classic symptoms of Chinese Restaurant Syndrome when it is consumed solo and on an empty stomach.

In a 2013 study, researchers gave healthy adults about 10 grams of MSG on average (a fairly large dose) without any food.

Almost all of them experienced headaches, as well as short-term increases in blood pressure and heart rate.

Bottom Line on MSG

Because MSG is generally used in small amounts as a flavoring (like salt), the likelihood that you'd eat it by itself is slim.

MSG might just be the most love-to-be-hated food additive, but scientific evidence fails to support its "bad guy" reputation.