MSG (in supplements)

Medically reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD — GMJ Editorial Board

What is MSG (in supplements)?

Monosodium glutamate (MSG) is the sodium salt of glutamic acid, a naturally occurring amino acid. While most commonly known as a food additive and flavor enhancer, MSG also appears in some dietary supplements, particularly those targeting athletic performance, cognitive function, or digestive health. In supplement form, MSG serves as a source of glutamate, which plays important roles in protein synthesis, neurotransmission, and cellular metabolism.

Glutamic acid is one of the 20 standard amino acids used to build proteins and is classified as a non-essential amino acid because the human body can produce it naturally. However, during periods of stress, illness, or intense physical activity, the body’s demand for glutamate may exceed its production capacity, making supplementation potentially beneficial in certain circumstances.

Health benefits & uses

Exercise performance and recovery (Limited evidence): Some research suggests that glutamate supplementation may support muscle protein synthesis and recovery following intense exercise. Glutamate serves as a precursor for other amino acids and plays a role in nitrogen metabolism during physical stress.

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Digestive health (Limited evidence): Glutamate is important for maintaining intestinal barrier function and supporting the growth of beneficial gut bacteria. Some studies indicate that glutamate supplementation may help maintain gut integrity during periods of stress or illness, though more human research is needed.

Cognitive function (Limited evidence): As a precursor to the neurotransmitter glutamate in the brain, MSG supplementation has been investigated for potential cognitive benefits. However, the blood-brain barrier limits the direct transfer of dietary glutamate to the brain, and evidence for cognitive enhancement remains inconclusive.

Immune system support (Limited evidence): Glutamate plays a role in immune cell function and may support the body’s defense mechanisms during periods of stress. Some research suggests potential benefits for maintaining immune function, but more robust clinical trials are needed.

How it works

When consumed, MSG dissociates into sodium and glutamate ions in the digestive system. The glutamate is then absorbed and can be used for various metabolic processes throughout the body. Glutamate serves as a building block for proteins, acts as a fuel source for rapidly dividing cells (particularly in the intestines and immune system), and participates in the synthesis of other amino acids like glutamine and GABA.

In muscle tissue, glutamate can be converted to glutamine, which helps maintain nitrogen balance and supports protein synthesis. In the digestive system, glutamate serves as a preferred fuel source for intestinal cells and may help maintain the integrity of the gut barrier.

Dosage

There is no established RDA or UL for MSG as a supplement ingredient. Typical dosages in supplements range from 500mg to 3000mg daily, often divided into multiple doses. The appropriate dosage varies significantly based on individual needs, health status, and the specific health goals being targeted.

For athletic performance applications, doses of 1000-3000mg daily are commonly used, while digestive health formulations may contain 500-1500mg daily. It’s important to consult with a healthcare provider before starting MSG supplementation, especially at higher doses or for extended periods.

Food sources

Glutamate occurs naturally in many foods, including tomatoes, mushrooms, aged cheeses, soy sauce, and fermented foods. Protein-rich foods like meat, fish, and dairy products also contain significant amounts of bound glutamate. Seaweed and kombu (kelp) are particularly rich natural sources of glutamate.

The average diet provides approximately 10-20 grams of glutamate daily from natural food sources, with an additional 0.5-1 gram potentially coming from added MSG in processed foods. This natural intake far exceeds typical supplement dosages.

Safety & side effects

MSG supplementation is generally considered safe for most healthy adults when used appropriately. The FDA classifies MSG as “Generally Recognized as Safe” (GRAS). However, some individuals may experience sensitivity reactions, including headaches, nausea, sweating, or flushing, particularly with large doses taken on an empty stomach.

These reactions are typically mild and short-lived. Starting with lower doses and taking MSG supplements with food can help minimize potential side effects. Individuals with severe asthma should exercise caution, as some case reports suggest potential respiratory symptoms in sensitive individuals, though well-controlled studies have not consistently demonstrated this association.

Interactions

MSG supplements may interact with certain medications, particularly those affecting neurotransmitter systems. Theoretical concerns exist regarding interactions with medications that affect glutamate signaling in the brain, such as certain anticonvulsants or psychiatric medications.

MSG may also affect sodium balance, so individuals taking medications for blood pressure or heart conditions should monitor their total sodium intake when using MSG supplements. Additionally, MSG might interact with other amino acid supplements, potentially affecting their absorption or utilization.

Who should be cautious

Individuals with known MSG sensitivity should avoid supplements containing this ingredient. People with severe asthma, those on sodium-restricted diets, and individuals with kidney disease should consult healthcare providers before using MSG supplements due to the sodium content and potential effects on electrolyte balance.

Pregnant and breastfeeding women should exercise caution and seek medical advice before supplementing with MSG. Children and adolescents should only use MSG supplements under professional guidance, as their amino acid requirements differ from adults.

Frequently asked questions

Is MSG in supplements the same as the MSG used in cooking?

Yes, chemically they are identical. Both supplement and food-grade MSG are monosodium glutamate with the same molecular structure and properties. The difference lies primarily in purity standards and intended use.

Can MSG supplements cause the same reactions as MSG in food?

Potentially, yes. Individuals who experience sensitivity reactions to MSG in food may also react to MSG in supplement form. The concentration and timing of consumption may influence the likelihood and severity of any reactions.

Do I need MSG supplements if I eat a balanced diet?

For most healthy individuals, a balanced diet provides adequate glutamate. Supplementation may only be beneficial in specific circumstances such as intense athletic training, recovery from illness, or specific health conditions under medical supervision.

How long does it take to see benefits from MSG supplementation?

This varies depending on the intended use. For exercise-related applications, some effects may be noticed within days to weeks, while benefits for digestive health or immune support may take longer to manifest and are less well-established.

Can MSG supplements help with weight management?

There is limited evidence supporting MSG supplementation specifically for weight management. While glutamate plays roles in metabolism, more research is needed to establish any direct benefits for weight control.