[7][8] MSG, along with disodium ribonucleotides, is commonly used and found in stock (bouillon) cubes, soups, ramen, gravy, stews, condiments, savory snacks, etc.

[13] The basic sensory function of MSG is attributed to its ability to enhance savory taste-active compounds when added in the proper concentration.

[7] The optimal concentration varies by food; in clear soup, the "pleasure score" rapidly falls with the addition of more than one gram of MSG per 100 mL.

[2][19] A popular belief is that MSG can cause headaches and other feelings of discomfort, but blinded tests have not provided strong evidence of this.

[10] International bodies governing food additives currently consider MSG safe for human consumption as a flavor enhancer.

[28][29] Although several studies have investigated anecdotal links between MSG and asthma, current evidence does not support a causal association.

The studies conducted to date on Chinese restaurant syndrome (CRS) have largely failed to demonstrate a causal association with MSG.

In general, foods providing metabolizable carbohydrates significantly attenuate peak plasma glutamate levels at doses up to 150mg/kg body weight.

The FASEB evaluation concluded, "sufficient evidence exists to indicate some individuals may experience manifestations of CRS when exposed to a ≥3 g bolus dose of MSG in the absence of food".

The polyacrylic fiber industry began in Japan during the mid-1950s, and acrylonitrile was adopted as a base material to synthesize MSG.

[36] As of 2016, most MSG worldwide is produced by bacterial fermentation in a process similar to making vinegar or yogurt.

MSG does not break down during cooking and, like other amino acids, will exhibit a Maillard reaction (browning) in the presence of sugars at very high temperatures.

[42][43] Ikeda noticed that dashi, the Japanese broth of katsuobushi and kombu, had a unique taste not yet scientifically described (not sweet, salty, sour, or bitter).

However, the term "natural flavor/s" is used by the food industry for glutamic acid (chemically similar to MSG, lacking only the sodium ion).

[50] In 2024, the federal government lifted the ban on MSG, following objections from Japan and a review of scientific evidence by an expert committee.

[61][23] This letter was initially met with insider satirical responses, often using race as prop for humorous effect, within the medical community.

[59] During the discursive uptake in media, the conversations were recontextualized as legitimate while the race-based motivations of the humor were not parsed, which replicated historical racial prejudices.

[59] Despite the resulting public backlash, the Food and Drug Administration (FDA) did not remove MSG from their Generally Recognized as Safe list.

[62][63][64][65][66] Herein, specifically East Asian cuisine was targeted, whereas the widespread usage of MSG in Western processed food does not generate the same stigma.

[67] These kind of perceptions, such as the rhetoric of the so-called Chinese restaurant syndrome, have been attributed to xenophobic or racist biases.