E-numbers / Flavour enhancers / E620
also: L-glutamic acid · glutamate
A naturally occurring amino acid used to add savoury, meaty depth to food. The same compound that gives Parmesan and tomatoes their umami taste.
Scan a barcode to check a food for glutamic acid. NutraSafe Pro · £6.99/month · iOS
Regular high intake through processed foods may push total glutamate consumption above the level regulators set as their group limit, particularly for children eating multiple umami-seasoned products in one day.
Why it’s worth knowing. Regular high intake through processed foods may push total glutamate consumption above the level regulators set as their group limit, particularly for children eating multiple umami-seasoned products in one day.
Glutamic acid is one of the most abundant amino acids found naturally in protein-containing foods such as cheese, tomatoes, mushrooms, soy sauce and meat. As a food additive it is produced by bacterial fermentation of carbohydrates. It is the free (unbound) form of glutamate, the same molecule responsible for the umami taste found naturally in aged, fermented and slow-cooked foods.
Free glutamate activates taste receptors on the tongue that register umami, the fifth basic taste alongside sweet, sour, salty and bitter. Added to food it intensifies and rounds out savoury flavour, reduces the amount of salt needed to achieve the same palatability, and gives depth to products that would otherwise taste flat. In the body, glutamic acid is also a neurotransmitter precursor and a key intermediate in protein metabolism.
Stock cubes, instant noodles, crisps, flavoured snack foods, soup powders, ready meals, savoury sauces, seasoning blends and processed meat products. It is used alongside or interchangeably with its salts E621 (monosodium glutamate), E622 (potassium glutamate), E623 (calcium glutamate), E624 (ammonium glutamate) and E625 (magnesium glutamate). On a UK label it appears as 'glutamic acid', 'E620', or as part of 'flavour enhancers (E620)'. Products may also list one of the glutamate salts (E621 to E625) instead.
In 2017 EFSA reviewed all six glutamate additives (E620 to E625) together. The panel set a conservative group ADI of 30 mg per kilogram of body weight per day based on a high-quality animal study. When they modelled how much people actually eat, they found that high consumers, especially children, could exceed this group limit when multiple glutamate-seasoned products are eaten in a single day. EFSA concluded the additives did not raise genotoxicity concerns, but the potential for dietary overexposure in high consumers was flagged as the primary concern.
EFSA established a conservative group ADI of 30 mg/kg bw/day for glutamic acid and its salts (E620 to E625), based on a no-observed-adverse-effect level from a 13-week rat study, applying a 100-fold uncertainty factor.
Estimated dietary exposure to glutamates from additive use exceeded the group ADI in a substantial proportion of high-consuming children and adolescents across European populations, when additive intake was combined with naturally occurring glutamate from protein-rich foods.
For decades people have reported headaches, flushing, chest tightness and sweating after eating Chinese restaurant food, a cluster labelled 'Chinese restaurant syndrome'. Multiple double-blind placebo-controlled trials have failed to reliably reproduce these symptoms when glutamate is given without the knowledge of participants. EFSA concluded in 2017 that the available evidence did not support a causal link between glutamate intakes from food and these reported symptoms at normal dietary levels. The association remains controversial and some researchers argue study doses did not reflect high real-world exposure.
Double-blind, placebo-controlled challenge studies have generally failed to confirm a consistent causal link between MSG intake and the cluster of symptoms reported as 'Chinese restaurant syndrome' when participants were unaware of which treatment they received.
A systematic review found that while some individuals self-reported sensitivity to MSG, robust double-blind challenge studies did not consistently reproduce symptom provocation at doses representative of normal dietary intake.
Glutamic acid is the main excitatory neurotransmitter in the brain. This has led to concerns that dietary glutamate from additives might cross the blood-brain barrier and overstimulate neurons. The available evidence suggests that dietary glutamate is almost entirely metabolised in the gut and does not meaningfully raise blood glutamate levels at typical food intake levels. However, brain glutamate levels do rise after very large oral doses in animal models, and the picture in individuals with compromised gut or blood-brain barrier function is less certain.
In healthy adults, the gut extracts approximately 95% of ingested glutamate before it reaches systemic circulation, limiting plasma and brain exposure from dietary sources.
In animal studies, very large oral doses of glutamate raised brain glutamate concentrations and produced neurotoxic lesions in the hypothalamus of neonatal rodents. These doses far exceed typical human dietary exposure and neonatal rodents lack the blood-brain barrier maturity of adult humans.
People who believe they are sensitive to glutamates should check labels for E620, E621, E622, E623, E624 and E625, all listed individually. Parents of children who regularly eat multiple highly processed savoury products in a day may wish to consider total glutamate load given that children are the group most likely to exceed the group ADI. People on low-sodium diets sometimes use monosodium glutamate (E621) as a partial salt replacer, which can increase total glutamate intake without a corresponding sodium increase.
The science on glutamates sits in two distinct places. The question of whether MSG causes headaches and flushing in sensitive people has been studied extensively for decades, and rigorous blinded trials keep failing to reproduce the effect reliably. EFSA concluded the symptom link is not established at normal dietary levels. The concern that did emerge from the 2017 review is more structural: when you add up how much glutamate people eat across all the seasoned processed products in a typical day, high consumers particularly children can exceed the group limit regulators set. That is a population-level dietary pattern question, not a toxicology emergency. The animal findings on neonatal neurotoxicity used doses far beyond dietary exposure and involved species with different blood-brain barrier development to humans. The honest summary: the MSG-headache story is weaker than its reputation; the overexposure concern in heavy processed-food eaters is real but modest in absolute terms.
No. Glutamic acid (E620) is approved for use as a flavour enhancer in the UK under assimilated EU food additive law retained after Brexit. It remains on the UK FSA approved-additives list.
The 'Chinese restaurant syndrome' and MSG headache claims have been studied in double-blind trials for decades. Rigorous blinded studies have generally failed to consistently reproduce the reported symptoms when participants did not know whether they had received glutamate or a placebo. EFSA concluded in 2017 that the evidence did not establish a causal link at normal dietary levels. Some individuals report subjective sensitivity, but the controlled evidence is weak.
Stock cubes, instant noodles, crisps and savoury snack foods, soup powders, ready meals, processed meat products, savoury sauces and seasoning blends. It may appear on the label as 'glutamic acid', 'E620', or alongside its salts E621 to E625.
Yes. Commercial glutamic acid used as a food additive is produced by bacterial fermentation of plant-derived carbohydrates such as sugar cane molasses, not from animal sources. The additive itself is vegan.
Last reviewed: 20 June 2026
It's the only app that does thisUKJaneK
You Need This AppGmac2005
Best AppGK getting skinny UK App Store reviews
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
NutraSafe Pro · £6.99/month · iOS
