Red 40 is not banned in the UK. It is legally authorized as a food additive in England, Scotland, and Wales under its European designation E 129 (Allura Red AC). However, the UK does impose stricter requirements than the United States, which is likely why this misconception is so widespread. Any food or drink containing Red 40 must carry a warning label about its potential effects on children’s behavior.
What the UK Actually Requires
Since July 2010, any food or drink sold in the UK that contains Red 40 must display a specific warning on the packaging: “Allura Red (E 129): may have an adverse effect on activity and attention in children.” This mandatory labeling applies to Red 40 and five other artificial colors collectively known as the “Southampton Six,” named after the university study that prompted the regulation.
This warning requirement has had a powerful indirect effect. Most major UK food manufacturers voluntarily reformulated their products to remove these dyes rather than print a warning that would discourage parents from buying them. The result is that Red 40 is far less common in UK grocery stores than in American ones, even though it remains perfectly legal to use. Walk through a British supermarket and you’ll find many familiar brands using natural colorings like beetroot extract or paprika instead of synthetic dyes. This voluntary shift, driven by market pressure rather than legal prohibition, is often mistaken for an outright ban.
Why the UK Restricted Red 40
The warning label traces back to a 2007 study published in The Lancet by researchers at the University of Southampton. The trial tested two different mixtures of artificial food colors (including Red 40) and a preservative called sodium benzoate on children aged 3 and 8 to 9. The children were given drinks containing these additives or a placebo, and their behavior was tracked by parents, teachers, and through computerized attention tests.
Both age groups showed measurably increased hyperactivity when consuming the additive mixtures compared to the placebo. Three-year-olds exposed to one of the mixtures showed a statistically significant increase in hyperactive behavior, with an effect size of 0.20. The older children showed significant effects from both mixtures. The researchers concluded that artificial colors or the preservative, or some combination, increased hyperactivity in the general population of children, not just in those already diagnosed with attention disorders.
The effect sizes were modest, meaning the behavioral changes were real but not dramatic for most children. Still, the European Food Safety Authority reviewed the data and acknowledged that some children who consume large amounts of foods and drinks containing Red 40 could exceed safe intake levels. The UK government decided that a mandatory warning was warranted, giving parents the information to make their own choices.
How the UK Differs From the US
In the United States, Red 40 is the most widely used artificial food dye. It appears in candy, cereals, snack foods, beverages, and even medications with no warning label required. The FDA has reviewed the same body of evidence and concluded that a causal link between artificial colors and hyperactivity in the general child population has not been definitively established, though it acknowledges that some sensitive children may be affected.
The UK takes a precautionary approach: the dye is allowed, but consumers are informed of the risk. The US takes a permissive approach: the dye is allowed without additional labeling. In practice, the UK’s labeling rule has done more to reduce Red 40 consumption than many outright bans would, because companies chose to reformulate rather than scare off customers. California passed its own warning label law for synthetic food dyes in 2023, becoming the first US state to adopt a similar strategy.
Red 40 in Other Countries
The European Union follows the same mandatory warning label rule that the UK adopted before Brexit, and most EU manufacturers have similarly moved away from Red 40 voluntarily. The dye is not banned in the EU either. Some countries outside Europe have taken harder stances on various artificial colors, but Red 40 specifically remains one of the most globally permitted synthetic dyes. It is approved in Canada, Australia, New Zealand, and many countries across Asia and South America.
The confusion often stems from the fact that several other red dyes are banned in various countries. Red No. 2 (amaranth), for example, was banned in the US in 1976 but remains permitted in some other markets. Red 40 was actually developed as a replacement for Red No. 2 and has a different chemical profile and safety record.
What This Means in Practice
If you’re buying food in the UK, you won’t find Red 40 in most mainstream products simply because manufacturers removed it voluntarily. But it can still appear in imported foods, specialty items, and certain brands that chose to keep the dye and print the warning label. Check the ingredients list for “Allura Red AC” or “E 129” if you want to avoid it. If you’re comparing UK and US versions of the same product, the UK version will often use natural colorings while the American version uses Red 40, even when both are made by the same company.