What is it?
Brilliant Blue FCF is a man-made blue dye made from petroleum-based chemicals. It belongs to a different family from the azo dyes in the Southampton Six, so UK packs do not need the hyperactivity warning for it.
Brilliant Blue
also: Brilliant Blue FCF · FD&C Blue No. 1 · Acid Blue 9 · CI 42090
A synthetic bright-blue petroleum-derived dye used to colour sweets, ice lollies, sports drinks and tinned peas.
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Sweeteners (Sorbitol, Aspartame, Sucralose, Acesulfame K), Flavourings, Anti-Caking Agent (Magnesium Salts of Fatty Acids), Colour (Brilliant Blue FCF)
E133
Brilliant Blue
In rat and mouse studies it changed blood cell counts and immune markers, and slowed an early reflex in young mice.
VeganVegetarian
UK supermarket foods that declare E133: 168 of the 43,325 we checked (0.4%)
Counted by its code or its name in the ingredient list.
Most of these labels print the code: 57% show “E133”.
Counted by NutraSafe from UK supermarket ingredient lists, September 2026. How we counted
How common it is in UK food, by aisle
- Chocolate and sweets53 products2.6% of 2,045
- Soft drinks and juices33 products1.3% of 2,627
- Cakes, biscuits and desserts23 products0.6% of 3,715
- Crisps and savoury snacks16 products0.5% of 3,428
What Brilliant Blue is, what it does and where you will see it
Why it’s worth knowing. In rat and mouse studies it changed blood cell counts and immune markers, and slowed an early reflex in young mice. In a lab test on nerve cells it did more harm mixed with MSG than either did alone. The US is working with food makers on a voluntary phase-out by the end of 2026. The UK and EU still approve it.
What does it do?
It turns food and drink bright blue. Mixed with a yellow dye such as tartrazine (E102) it makes green, which is how tinned mushy peas get their colour. It adds no flavour.
Where you will see it
Blue and blue-raspberry sweets, ice lollies and slush drinks, blue Smarties and pick-and-mix, sports and energy drinks, cake icing, blueberry ice cream, tinned mushy peas, and some packet soups and jellies. Labels call it Brilliant Blue FCF or E133.
What the science says
The daily limit was cut
The daily limit was cut from 10 to 6mg per kg of body weight, after a more cautious reading of long-term rat studies.
Reviewers cut the daily limit from 10 to 6mg per kg of body weight a day.
2010Regulator reviewEFSA Panel on Food Additives and Nutrient Sources (ANS), Scientific Opinion on the re-evaluation of Brilliant Blue FCF (E 133) as a food additive, EFSA Journal 1853
The international expert committee set the daily limit at 6mg per kg of body weight at its 84th meeting, using the same rat result. It noted that children with the highest intakes take in around 5mg per kg a day, just under the limit.
2017Regulator reviewJECFA (Joint FAO/WHO Expert Committee on Food Additives), 84th meeting, WHO Food Additives Series
Slowed an early reflex in young mice at a high dose
Mice fed the dye over two generations had pups that were slower to develop an early reflex, and adult females explored their cage differently, at the highest dose tested. A 2022 review looking for a link between blue dye and ADHD symptoms in children found only 4 studies from 20 years of research. It noted the changes seen in animals at high doses.
Mice fed Brilliant Blue FCF at 0.72% of their diet across two generations had pups that were slower to turn themselves upright on day 4 after birth, and adult females explored differently. The authors described the effects as limited but statistically significant.
2012Animal studyTanaka T et al., Reproductive and neurobehavioral effects of Brilliant Blue FCF in mice, Birth Defects Research Part B: Developmental and Reproductive Toxicology
A review found only four studies that looked at blue food colouring and ADHD symptoms in children. It concluded that research on Blue No. 1 or Blue No. 2 in children is very limited and more is needed.
2022Review of studiesRambler et al., A Review of the Association of Blue Food Coloring With Attention Deficit Hyperactivity Disorder Symptoms in Children, Cureus
Did more harm to nerve cells when mixed with MSG, in a lab dish
A 2006 study on nerve cells growing in a dish found that Brilliant Blue together with glutamic acid, the active part of MSG, stunted their growth more than either did alone. The authors said the amounts used could in theory come from a typical snack and drink eaten together.
Brilliant Blue FCF combined with glutamic acid held back the growth of mouse nerve cells in a dish more than either alone. The authors said the amounts could in theory come from a typical children's snack and drink.
2006Lab study on cellsLau K, McLean WG, Williams DP, Howard CV, Synergistic interactions between commonly used food additives in a developmental neurotoxicity test, Toxicological Sciences
Changed blood and immune markers in rats, below the daily limit
Rats given 1.2mg per kg of body weight a day for 90 days, under the daily limit of 6mg, had fewer red and white blood cells, less haemoglobin and fewer platelets. Their immune and inflammation markers changed too.
Male rats given 1.2mg per kg of body weight a day for 90 days showed signs of a type of anaemia and low platelets, fewer antibodies, and more inflammation signals in the spleen.
2021Animal studyModulation of immune functions, inflammatory response, and cytokine production following long-term oral exposure to three food additives: thiabendazole, monosodium glutamate, and brilliant blue in rats, ScienceDirect / PubMed PMID 34182247
The US is phasing it out by the end of 2026, while the UK and EU still approve it
In April 2025 the US health department and the FDA announced a voluntary deal with food makers to remove Blue No. 1, the US name for Brilliant Blue FCF, and five other petroleum-based dyes by the end of 2026. It is not a legal ban and does not apply in the UK or EU, where the dye is approved. California has separately passed a law taking it out of school food by December 2027.
The US health department and the FDA said in April 2025 they would work with food makers to remove Blue No. 1 and five other man-made dyes from US food by the end of 2026, as part of a move away from petroleum-based colours.
2025Government announcementUS HHS/FDA press announcement, HHS.gov
Where it stands with the regulators
Approved in the UK and the EU
Daily limit. 6mg per kg of body weight a day, about 420mg for a 70kg adult (European reviewers 2010, international committee 2017).
- Legal basis
- On the Food Standards Agency's approved list for England, Scotland and Wales
- Permitted foods
- Sweets · Ice cream and frozen desserts · Soft drinks, sports drinks and flavoured waters · Tinned and processed vegetables, including mushy peas · Packet soups and sauces · Cake icing, decorations and coatings · Dairy desserts and flavoured milks · Ice lollies
- Maximum levels
- 150 to 300mg per kg of food, depending on the food. It shares a combined limit with some other colours.
- History
- First assessed by the international expert committee in 1959 and 1964. Europe set a daily limit of 10mg per kg in 1984 and cut it to 6mg in 2010. The international committee agreed 6mg in 2017. It does not need the Southampton hyperactivity warning carried by E102, E104, E110, E122, E124 and E129. In April 2025 the US began a voluntary phase-out by the end of 2026. The UK and EU have announced nothing similar.
Who should be careful
Anyone who gets skin or breathing reactions after brightly coloured food and drink may react to this dye. It is not one of the allergens UK law makes labels declare, so the ingredients list is the only place to check for Brilliant Blue FCF or E133. Parents who want to limit man-made dyes should look for the same names. Our food additive scanner reads that list off the barcode and names the colours in it.
The honest read
European and international reviewers set a daily limit for it. The picture is not clean, though. The limit was cut from 10 to 6mg per kg between 1984 and 2010 after new long-term data. In animals it has changed behaviour in young mice and blood and immune markers in rats, the rat changes at a dose below the limit. In a lab dish, mixed with MSG, it harmed developing nerve cells more than either did alone.
Exposure estimates put the children with the highest intakes close to the daily limit. The US is phasing it out voluntarily by the end of 2026, citing a wider move away from petroleum-based dyes, though that does not bind UK or EU makers.
Common questions about Brilliant Blue
Is E133 banned in the UK?
No. It is on the Food Standards Agency's list of approved additives. It also does not need the hyperactivity warning that the Southampton Six colours (E102, E104, E110, E122, E124 and E129) carry.
Is E133 harmful?
It is approved with a daily limit of 6mg per kg of body weight. Some rat and mouse studies found changes to blood, immune markers and an early reflex, and a lab study found more harm to nerve cells when it was mixed with MSG. Children who eat a lot of coloured food and drink come close to the limit.
Why is the US phasing out Brilliant Blue FCF?
In April 2025 the US health department and the FDA agreed a voluntary deal with food makers to remove Blue No. 1, the US name for Brilliant Blue FCF, and five other petroleum-based dyes by the end of 2026, as part of a wider move away from petroleum-based colours. It is not a legal ban, and it does not apply in the UK or EU.
What foods contain E133?
Blue and blue-raspberry sweets, ice lollies, slush drinks and sports drinks are the most common. It is also in some cake icing, blue ice cream, packet soups, jellies and tinned mushy peas, where it is mixed with a yellow dye to make green. Labels call it Brilliant Blue FCF or E133.
Is E133 vegan?
It contains no animal ingredients, because it is made from petroleum-based chemicals. Some versions use an aluminium form of the dye. Food dyes were tested on animals to set their limits, which matters to some vegans. UK labelling rules do not flag it as non-vegan.
Sources
- UK FSA Regulated Products Database: E133 Brilliant Blue FCF
- EFSA Panel on Food Additives (ANS): Scientific Opinion on the re-evaluation of Brilliant Blue FCF (E 133) as a food additive, EFSA Journal 2010
- JECFA: Brilliant Blue FCF monograph and evaluation summary, WHO Food Additives database
- Lau K et al., Synergistic interactions between commonly used food additives in a developmental neurotoxicity test, Toxicological Sciences, 2006
- Tanaka T et al., Reproductive and neurobehavioral effects of Brilliant Blue FCF in mice, Birth Defects Research Part B, 2012
- Rambler et al., A Review of the Association of Blue Food Coloring With Attention Deficit Hyperactivity Disorder Symptoms in Children, Cureus, 2022
- Amchova P et al., Food Safety and Health Concerns of Synthetic Food Colors: An Update, Toxics, 2024
- Olas B et al., The Effects of Natural and Synthetic Blue Dyes on Human Health: A Review of Current Knowledge and Therapeutic Perspectives, Advances in Nutrition, 2021
- Modulation of immune functions, inflammatory response, and cytokine production following long-term oral exposure to three food additives: thiabendazole, monosodium glutamate, and brilliant blue in rats, PubMed PMID 34182247
- US HHS/FDA press announcement: HHS, FDA to Phase Out Petroleum-Based Synthetic Dyes in Nation's Food Supply
- Wikipedia: Brilliant blue FCF
- US FDA (22 April 2025) HHS, FDA to Phase Out Petroleum-Based Synthetic Dyes in Nation's Food Supply
Last reviewed: 9 November 2026
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