Food science
MSG: good or bad for you?
Monosodium glutamate (MSG) is one of the most argued-about ingredients on the internet - yet decades of safety reviews say it is fine for most people at the amounts used in everyday cooking. Here is what it actually is, where you meet it, and how a single 1960s letter created a myth that will not go away.
Short answer: for the general population, MSG is not something to fear at normal dietary levels. If a specific meal disagrees with you, that is worth listening to - but blame the whole plate (salt, fat, portion size, wine) before you single out glutamate.
Evidence-led food education from Meal Pilot. Not personalised medical or allergy advice.
Safe at normal intakes
Major regulators (including the UK FSA and EFSA) allow MSG as a food additive when used within limits. It is not a toxin at the amounts used in cooking.
Glutamate is already in food
Tomatoes, parmesan, mushrooms, meat and breast milk all contain glutamate. MSG is simply a concentrated, purified form of the same amino acid.
Blinded studies rarely find harm
When people do not know whether they are eating MSG, reported “reactions” largely disappear in controlled trials - a strong sign the scare story was overstated.
What is MSG?
MSG is the sodium salt of glutamic acid - one of the building blocks of protein. It dissolves in water and delivers umami, the savoury “moreish” taste you already get from parmesan rind, miso, soy sauce and slow-cooked stock.
On UK labels it may appear as monosodium glutamate or additive number E621. A typical pinch in home cooking is far below the amounts tested in regulatory safety studies.
Natural glutamate vs added MSG
Your body does not distinguish neatly between glutamate from a tomato and glutamate from a shaker. The difference is dose and context: a dusting of MSG in a stir-fry is comparable to loading a dish with parmesan, mushrooms and soy - ingredients we happily call “real food”.
Parmesan
Very high natural glutamate
Tomatoes
Ripe tomatoes & passata
Mushrooms
Especially dried shiitake
Miso & soy sauce
Fermented savoury bases
Fish sauce
South-East Asian cooking
Meat & fish
Aged, roasted or cured
Where you meet it in real life
Home cooking
A pinch in stir-fries, ramen broth, gravies or marinades deepens savoury flavour so you can use less salt. Many UK supermarkets sell it as “flavour enhancer” or E621.
Restaurants
Chefs use glutamate-rich ingredients (stock, soy sauce, fish sauce, miso, parmesan) and sometimes added MSG in seasoning blends - especially in East and South-East Asian kitchens, but also in Western stocks and crisps.
Takeaways & ready meals
It often sits inside “seasoning”, “flavouring” or “spice mix” rather than on the label as MSG. That does not make the meal dangerous - it usually means “more umami per spoonful”.
Supermarket shelves
Crisps, instant noodles, soup pots, gravy granules and frozen meals may contain E621. Check ingredients if you are avoiding it for personal preference.
Salt is still the bigger story
MSG contains sodium, but gram-for-gram it carries less sodium than table salt. Many cooks use a little MSG to boost flavour so they can reduce salt - though the total sodium in a takeaway curry or instant noodle pot still comes mainly from salt, soy sauce and seasoning blends. UK adults are advised to keep salt around 6 g per day; focus there first.
Where the bad rumour came from
Umami is named
Japanese chemist Kikunae Ikeda identifies glutamic acid as the savoury taste in kelp broth - the fifth basic taste, alongside sweet, sour, salty and bitter.
MSG is first made
Ikeda patents monosodium glutamate as a seasoning. It spreads through Asian cooking and later global food manufacturing.
The rumour begins
A letter to the New England Journal of Medicine coins “Chinese restaurant syndrome” - numbness and palpitations after American-Chinese meals. The author speculated MSG; the letter was anecdotal, not a study.
Science pushes back
Double-blind trials ask volunteers to swallow MSG or placebo in capsules or juice. Most find no consistent symptoms when people cannot see what they are eating.
Regulators stay calm
The FSA lists E621 as an approved additive. EFSA reviewed glutamates and found no safety concern at current dietary exposure for the general population.
Myth vs evidence
Often claimed
MSG is an artificial poison.
Evidence says
It is the sodium salt of glutamic acid - an amino acid your body makes and uses every day.
Often claimed
Only Chinese food has it.
Evidence says
Glutamate-rich flavour appears in Italian, British and American foods too (stock cubes, crisps, gravy, cheese).
Often claimed
“No added MSG” means no glutamate.
Evidence says
Tomato, mushroom, parmesan and soy still add plenty of natural glutamate.
Often claimed
It causes headaches in everyone.
Evidence says
Some people feel unwell after certain meals; blinded studies rarely pin that on MSG alone. Triggers are often the whole meal (salt, alcohol, hunger, anxiety).
What if you still react?
A minority of people report headaches or flushing after certain restaurant meals. That experience is real - but when researchers test MSG in capsules or drinks and participants do not know what they are getting, consistent reactions are hard to reproduce. Triggers may be the whole eating episode: large portions, alcohol, dehydration, histamine-rich foods, or anxiety about the meal.
If you prefer to avoid MSG, check labels for E621 and ask about seasoning blends. You do not need to avoid tomatoes, cheese or mushrooms to skip added glutamate.
Quick wins
MSG in cooking is not the same as heavy salt - still watch total sodium.
Tomatoes, cheese and mushrooms contain natural glutamate too.
If you react to restaurant meals, the whole plate - not just MSG - may be the trigger.
Build a week around this advice
Written for Meal Pilot by Dr James, MBBS - a practising NHS GP in the United Kingdom. The information below reflects UK public-health guidance (including NHS Eatwell principles and SACN reference intakes). It is educational, not a personal prescription: always follow advice tailored to you by your own GP, practice nurse or registered dietitian.
Reviewed by
Meal Pilot editorial team with GP review
Sources
· UK FSA: E621 monosodium glutamate
· EFSA: Re-evaluation of glutamic acid and glutamates (2017)
· FDA: Questions and answers on MSG
· WHO/JECFA food additive evaluations (glutamic acid)
Important
This page summarises mainstream food-safety and nutrition science for general readers. It is not medical advice. If you have severe headaches, allergies, pregnancy-related needs, kidney disease or are on a sodium-restricted diet, follow guidance from your GP or dietitian.