Is MSG Actually Bad for You? What E621 Really Means

MSG stands for monosodium glutamate. Its European food-additive number is E621. It is the sodium salt of glutamic acid, an amino acid and a normal component of proteins. Glutamic acid is also naturally present in foods, and EFSA gives tomatoes, soy sauce and certain cheeses as examples.

MSG is added to food because it can enhance savoury flavour. On an Irish ingredients list you may see Flavour enhancer: monosodium glutamate or Flavour enhancer: E621. If the numbers are new to you, start with what E numbers are.

MSG is used as a flavour enhancer. It doesn't necessarily create a new flavour. It strengthens the savoury character a food already has. EFSA describes glutamates as being added to provide or enhance a savoury or meaty taste, the taste commonly called umami.

You'll often find flavour enhancers in highly seasoned foods such as:

• soups and broths
• sauces and seasonings
• savoury snacks
• some meat products and other prepared foods

That doesn't mean every product in those categories contains MSG. The ingredients list tells you whether a specific product does.

Yes, for authorised uses. E621 appears on the EU list of permitted food additives, and food sold in Ireland follows the European food-additive framework. The specific conditions of use depend on the type of food.

So an E number isn't a code a manufacturer invents. It identifies an additive inside the EU authorisation system. For other numbers you'll meet on the same labels, see 10 common food additives.

ADI means Acceptable Daily Intake: an estimate of the amount of a substance that can be consumed daily over a lifetime without an appreciable health risk. For glutamates, EFSA set 30 mg/kg body weight/day, expressed as glutamic acid.

It's a group ADI because it covers several related additives:

• E620 glutamic acid
• E621 monosodium glutamate
• E622 monopotassium glutamate
• E623 calcium diglutamate
• E624 monoammonium glutamate
• E625 magnesium diglutamate

It isn't a target you need to reach. It's a long-term risk-assessment benchmark.

As of 5 October 2026, the 2017 group ADI is still the published EFSA benchmark for glutamates. EFSA has kept gathering updated analytical and use-level data for E620 to E625, and its latest public data call, which included MSG, asked for submissions by 30 June 2026.

So the area is still being followed. That alone doesn't mean EFSA has reversed its earlier conclusion. Until a completed updated assessment says otherwise, the published group ADI is the relevant reference point.

The evidence is inconsistent. A systematic review of human studies found an important difference between MSG eaten with food and relatively high concentrations taken in liquids without food.

When MSG was eaten with food, most studies found no significant increase in headaches. Some studies using concentrated MSG without food did report more. The review also pointed to small study sizes, inconsistent results, unusually high doses and the difficulty of blinding strong MSG solutions, which taste distinctive.

The authors concluded the evidence wasn't strong enough to show that ordinary MSG consumption causes headaches. That's more accurate than "MSG causes headaches", and more accurate than "nobody can ever react to MSG".

MSG is not one of the 14 allergens that must be emphasised under EU food-information rules, such as milk, eggs, peanuts, nuts, gluten-containing cereals and soybeans.

That doesn't mean nobody ever reports symptoms after eating it. It means MSG sits outside the mandatory allergen-labelling system. An adverse reaction and a legally defined allergen aren't automatically the same thing.

It tells you something true about the recipe. But like "zero sugar", "high protein" or "no preservatives", it describes one thing. It doesn't tell you:

• how salty the product is
• whether it's high in saturated fat
• whether it contains fibre
• what else is in it
• how much you normally eat

Front-of-pack claims are useful. The mistake is treating one claim as the whole product. Our guide to reading an ingredients list covers the back of the pack.

Nobody should have to remember what every additive number means. If a product contains E621, Sláinte names it as monosodium glutamate, a flavour enhancer, and shows it alongside the product's nutrition and full ingredient list. That keeps E621 in context instead of turning it into the whole verdict.