Does MSG Dehydrate You? Separating Fact from Flavor Enhancer Fiction

October 10, 2025 •

3 min read

According to research published in the journal Nutrición Hospitalaria, chronic exposure to MSG may increase thirst sensation, but a more common link is tied to a person's sodium intake. So, does MSG dehydrate you in a way that regular salt doesn't, or is the perceived dehydration simply a result of the total sodium load in a meal?

Quick Summary

The sensation of thirst associated with consuming MSG is a direct response to its sodium content, not a unique dehydrating property. Just like table salt, excessive MSG raises blood sodium, prompting the body to signal for more water to restore balance. Blame is often misplaced on MSG rather than the overall high-sodium nature of many processed foods containing it.

Key Points

MSG contains sodium: As a sodium salt of glutamic acid, MSG contributes to the overall sodium load of a meal, which is the primary cause of increased thirst.
Thirst is a natural response: Increased sodium concentration in the blood signals the body to prompt thirst, encouraging fluid intake to restore electrolyte balance.
MSG vs. salt: MSG has significantly less sodium by weight than table salt, meaning it is not more dehydrating on a gram-for-gram basis.
Total sodium matters: The thirst often associated with MSG is more likely due to the high overall sodium content of processed and restaurant foods that contain it, not the MSG alone.
FDA classifies MSG as safe: The U.S. Food and Drug Administration considers MSG to be 'generally recognized as safe' (GRAS) for consumption.
Manage hydration holistically: To prevent thirst and maintain hydration, it's best to monitor total sodium intake from all food sources and ensure adequate fluid consumption.

Monosodium glutamate (MSG) is a food additive widely used to enhance flavor, known for providing a savory, or umami, taste. For decades, it has been linked with various health concerns, including headaches, flushing, and increased thirst. While the physiological link between high sodium intake and thirst is well-established, many mistakenly believe MSG has a special dehydrating effect. The reality is that MSG's impact on your body's hydration is tied directly to its sodium content, just like any other sodium-based ingredient, such as table salt.

The Role of Sodium in Hydration and Thirst

Your body meticulously regulates its electrolyte balance, a process that is essential for proper hydration. When you consume sodium, such as from table salt (sodium chloride) or MSG (monosodium glutamate), the concentration of sodium in your blood increases. The body's natural and healthy response to this is to trigger thirst. The sensation of thirst is your body's signal to drink more water to help dilute the elevated sodium concentration and restore balance. This is a fundamental physiological process, not a mysterious side effect.

How MSG Affects Sodium Levels

Sodium Source: MSG is a sodium salt of glutamic acid, an amino acid.
Blood Concentration: When consumed, the sodium ions from MSG enter the bloodstream, increasing the blood's sodium concentration and prompting the thirst response.
Comparison to Salt: While both MSG and table salt contain sodium, MSG contains only about one-third the amount of sodium as table salt by weight. This means you would need to consume a larger quantity of MSG than salt to get the same sodium load. However, foods containing MSG are often high in other sodium sources, such as soy sauce, broths, and preservatives, which collectively contribute to the overall sodium intake and subsequent thirst.

The Truth About 'Chinese Restaurant Syndrome'

The phenomenon known as 'Chinese Restaurant Syndrome' (CRS) historically blamed MSG for a variety of symptoms, including thirst, headaches, and flushing. However, extensive research and clinical studies have failed to provide consistent evidence linking MSG directly to this constellation of symptoms in the general population. The blame is more accurately placed on the total sodium content of the meal, which can be quite high in some restaurant preparations, combined with other potential factors or sensitivities. The FDA has classified MSG as “generally recognized as safe” (GRAS) for consumption.

Comparing MSG and Table Salt's Hydration Effects


Feature	MSG (Monosodium Glutamate)	Table Salt (Sodium Chloride)
Sodium Content	Lower (approx. 12% by weight)	Higher (approx. 39% by weight)
Primary Function	Umami flavor enhancer	Salty flavor enhancer
Effect on Thirst	Increases thirst due to its sodium content	Increases thirst due to its sodium content
Associated Foods	Processed foods, soups, sauces, restaurant dishes	General cooking, seasoning, processed snacks
Flavor Impact	Enhances savory, brothy flavors	Provides a direct salty taste

Managing Your Sodium and Hydration

Instead of focusing on MSG as a unique culprit for dehydration, it's more effective to manage your overall sodium intake and hydration practices. The following strategies can help you maintain proper fluid balance:

Monitor Overall Sodium: Pay attention to the total sodium content of processed foods, including soups, sauces, and ready-to-eat meals, not just those with added MSG.
Cook at Home: Preparing more meals at home allows you to control the exact amount of sodium you consume.
Read Food Labels: Check the nutrition facts panel for sodium levels to make informed choices.
Drink Water: Increase your water intake when you consume sodium-rich meals to help your body manage the electrolyte balance.
Choose Natural Foods: Incorporate more whole foods like fruits, vegetables, and lean proteins, which naturally contain less sodium. Many of these foods also contain potassium, which helps balance sodium levels.
Use Other Seasonings: Experiment with herbs and spices as alternatives to salt to add flavor without increasing your sodium load.

Conclusion: MSG is Not Uniquely Dehydrating

To put it simply, the notion that MSG uniquely dehydrates you is a misconception. Any feeling of increased thirst after consuming foods containing MSG is a direct result of the body's natural response to the meal's total sodium content, just as it would be with regular table salt. The most important takeaway for proper hydration and dietary health is to focus on managing your overall sodium intake from all sources, rather than singling out one flavor enhancer. By being mindful of your diet and increasing your fluid intake when necessary, you can ensure your body stays well-hydrated.

For more information on monosodium glutamate and its safety, you can review the FDA's stance on this food additive.

Frequently Asked Questions

You feel thirsty because MSG contains sodium. Your body is naturally signaling you to drink more water to dilute the higher sodium concentration in your blood and restore proper balance.

No, MSG is not more dehydrating than regular table salt. In fact, MSG contains only about one-third the amount of sodium as table salt by weight. The effect on hydration is primarily determined by the total amount of sodium consumed, regardless of the source.

'Chinese Restaurant Syndrome' (CRS) is a term for a collection of symptoms, including thirst and headaches, historically linked to MSG. However, extensive scientific research has not found a consistent link between MSG and these symptoms in the general population. High-sodium meals are a more likely cause.

Some people report mild, short-term sensitivities to MSG, which can include headaches, flushing, or numbness. For most people, there is no consistent evidence to support a connection, and the effects often occur only after very large doses in controlled settings.

To reduce thirst from a sodium-rich meal, the best approach is to increase your water intake. Drinking plenty of water helps your body manage the electrolyte balance and dilute the elevated sodium levels.

Yes, for most people, it is safe to eat foods that contain MSG. It has been classified as 'generally recognized as safe' (GRAS) by the FDA when consumed at normal levels.

Chemically, MSG is a sodium salt just like table salt. The body processes the sodium from MSG and other food sources in the same way. The key difference lies in the amount of sodium per gram and the resulting flavor profile.