Ingredient · Flavor
Monosodium Glutamate
The sodium salt of glutamic acid, added to deliver savoury depth. Glutamate occurs naturally in tomatoes, parmesan, and mushrooms, and the body does not distinguish added glutamate from the kind in whole foods.
also known as MSG, E621, Sodium glutamate
MSG's reputation and its evidence base have never really matched. Controlled trials have not reproduced the cluster of symptoms once attributed to it, and regulators in the US and EU both treat it as generally safe.
It is flagged here for a different reason: it contributes sodium, and its function is to make a formulation taste richer than its actual ingredients would. It also hides behind other names — yeast extract, hydrolysed vegetable protein, and autolysed yeast all supply free glutamate without the letters MSG appearing anywhere on the label.
Why it’s classified this way
Flagged less for its own toxicity — which controlled trials have not supported — than for its sodium contribution and the many names it hides behind.
References
- FDA statement on MSG
- EFSA re-evaluation of glutamic acid and glutamates