E621

E621 is the European food additive designation for monosodium glutamate (MSG), a flavor enhancer that intensifies the savory taste known as umami. MSG is the sodium salt of glutamic acid, one of the naturally occurring amino acids, and is widely used to enhance the mouthfeel and palatability of a variety of foods.

Chemically, MSG is produced commercially by fermentation of carbohydrate-rich substrates such as sugar beets, sugar cane, or molasses, using bacteria to produce glutamic acid, which is then neutralized with sodium to form MSG. In food products, it is typically used in small amounts to boost savory flavor in soups, sauces, snacks, seasonings, and processed meats. Its designation as E621 indicates regulatory approval within the European Union.

Regulation and safety assessments vary by jurisdiction but share a general conclusion that MSG is safe for the general population when consumed in typical amounts. In the United States, the FDA considers MSG to be generally recognized as safe (GRAS) for use in foods; in the EU, MSG is approved as a permitted additive under the E621 code. Some individuals report adverse symptoms such as headaches or flushing after consuming large quantities, a phenomenon sometimes referred to as MSG symptom complex, but extensive scientific reviews have found no consistent evidence of harm at usual consumption levels.

MSG contains about 12% sodium by weight, so its use contributes to total sodium intake. It is usually listed on ingredient labels as monosodium glutamate or MSG, and, in the EU, as E621.