What is it?
Monosodium glutamate (MSG) is the sodium salt of glutamic acid, an amino acid. It is made by fermenting starch, sugar beet, sugar cane or molasses with bacteria, then drying it into white crystals.
E-numbers / Flavour enhancers / E621
MSG
also: sodium glutamate · monosodium L-glutamate
A flavour enhancer made by fermentation that gives food a savoury, umami taste.
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Soybean Oil [45%], Chilli [25%], Onion [15%], Fermented Soybeans [ Soybeans, Water], Flavour Enhancer: [E621], Salt, Sugar, Sichuan Pepper Powder
E621
MSG
European reviewers found that in the UK and EU, infants, toddlers and children can go over the daily limit.
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UK supermarket foods that declare E621: 739 of the 43,325 we checked (1.7%)
Counted by its code or its name in the ingredient list.
Only 22% of these labels print “E621”. Most use the name: look for “monosodium glutamate”.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
How common it is in UK food, by aisle
- Crisps and savoury snacks252 products7.3% of 3,428
- Ready meals and pizza128 products2.6% of 4,833
- Fresh meat, poultry and fish113 products2.3% of 4,835
- Sauces, dressings and condiments100 products3.6% of 2,776
What MSG is, what it does and where you will see it
Why it’s worth knowing. European reviewers found that in the UK and EU, infants, toddlers and children can go over the daily limit. Large single doses taken without food have brought on short-lived headaches in some people.
What does it do?
It adds umami, the savoury fifth taste. Glutamate switches on taste receptors on the tongue and deepens the meaty, brothy flavour of a dish, so makers can make food more savoury without adding more meat, salt or stock.
Where you will see it
Crisps, stock cubes, instant noodles, gravy granules, ready meals, savoury snacks, soy and seasoning sauces, and takeaways. UK labels call it flavour enhancer (E621), monosodium glutamate or MSG.
What the science says
Some groups, especially children, go over the daily limit
In 2017 European reviewers set a shared daily limit for glutamic acid and glutamates of 30mg per kg of body weight, about 2g a day for an average adult, based on animal studies. They then found that real intakes can go over it, and at high intakes can reach doses linked to effects in people, for some groups, particularly infants, toddlers and children.
European reviewers set the daily limit at 30mg per kg of body weight, roughly 2g a day for an average adult, shared across E620 to E625.
2017Regulator reviewEFSA Journal
Average intakes went over the limit in infants, toddlers, children and teenagers. Among the people with the highest intakes, every age group went over it.
2017Regulator reviewEFSA Journal
Doses above the limit have been linked to effects in people: the cluster of MSG symptoms above 42.9mg per kg a day, headache at around 85.8mg per kg, a rise in blood pressure at 150mg per kg, and higher insulin above 143mg per kg. All sit above the daily limit.
2017Regulator reviewEFSA Journal
Short-lived symptoms after large doses without food
Large single doses taken without food have brought on short-lived symptoms in some people.
A US review found short-lived, generally mild symptoms (headache, numbness, flushing, tingling, a racing heart, drowsiness) in some sensitive people after 3g or more of MSG taken without food.
1995Regulator reviewUS FDA / FASEB report
Where it stands with the regulators
Approved in Great Britain and the EU as flavour enhancer E621. Also approved in the US.
Daily limit. 30mg per kg of body weight a day, measured as glutamic acid, shared across the glutamates (European reviewers, 2017).
- Legal basis
- On the Food Standards Agency's list of approved additives for Great Britain
- Permitted foods
- A wide range of processed savoury foods, including seasonings, snacks, soups, sauces, stocks and ready meals, within set limits
- Maximum levels
- Usually 10g per kg for the glutamate group (E620 to E625) in most foods, with separate limits for seasonings and condiments, measured as glutamic acid.
- History
- Kikunae Ikeda first isolated it from kombu seaweed in 1908, and it went on sale in 1909. The international committee had earlier set no numerical daily limit for glutamates. In 2017 European reviewers replaced that with a numerical limit of 30mg per kg a day, flagged that current intakes can go over it for some groups, and recommended lower permitted levels.
Who should be careful
Parents keeping an eye on how many heavily seasoned processed snacks young children eat, and anyone who has noticed a reaction after large MSG-heavy meals, can limit it by checking for flavour enhancer (E621), monosodium glutamate or MSG on the label.
The honest read
The 2017 European review found intake can go over its proposed daily limit for infants and children, which is why it set a numerical limit and asked for lower permitted levels.
Common questions about MSG
Is E621 (MSG) banned in the UK?
No. E621 is an approved flavour enhancer in Great Britain and the EU, and it is approved in the US too. The 2017 European review kept it allowed but set a daily limit and recommended lower maximum levels in food.
Does MSG cause headaches?
European reviewers noted headache in studies at around 85.8mg per kg of body weight a day, and a US review found short-lived symptoms in some sensitive people after 3g or more taken without food.
What foods contain E621?
Crisps, stock cubes, instant noodles, gravy granules, ready meals, savoury snacks, soy and seasoning sauces, and many takeaways.
Is E621 vegan?
Yes. It is made by fermenting plant sources such as starch, sugar beet, sugar cane or molasses with bacteria, with nothing from animals.
Sources
- EFSA (2017): Re-evaluation of glutamic acid (E620), sodium glutamate (E621) and other glutamates (E622-E625) as food additives, EFSA Journal
- US FDA: Questions and Answers on Monosodium Glutamate (MSG)
- EU Regulation 1333/2008 on food additives (retained in GB law; FSA approved additives list)
Last reviewed: 9 November 2026
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