A savory food additive. It is commonly used in snacks, chinese food, flavorings, and other consumable items. It has the notable property in that unlike appetite suppressants, MSG makes you want to eat more.

As it is a white powder similar in appearance to salt and sugar, depictions here more often refer to a written, or sometimes chemical, depiction of the concept.

The European Food Safety Authority gives it the food additive number of 621, thus spawning jokes about the extreme, probably intentional, similarity to the site name.