Is Red 40 Bad for You? What the Evidence Says

Red 40 is not proven harmful for most people, but it may not suit everyone. Controlled trials suggest dye mixtures that include it can increase hyperactivity in some children. It is not banned in Europe: it is allowed as E129 with a warning label. In the US the FDA is asking companies to drop it by the end of 2027.

If you have noticed a child bouncing off the walls after a brightly colored snack and wondered whether the dye had something to do with it, you are not alone, and the question is reasonable. Here is what the research actually supports.

What is Red 40?

Red 40, officially FD&C Red No. 40 and also known as Allura Red AC, is a synthetic dye made from petroleum-derived chemicals. It is one of the “certified” color additives in the US: every batch is tested and certified by the FDA before it can be sold. It is among the most widely used food dyes in the country.

Is Red 40 banned in Europe?

No. This is one of the most common myths about food dyes. Red 40 is permitted in the European Union under the name E129. Since 2010, EU law (Annex V of Regulation 1333/2008) has required foods containing E129, or any of five other dyes, to carry this warning:

“[name or E number of the colour(s)]: may have an adverse effect on activity and attention in children.”

The other five are E102 (tartrazine, sold in the US as Yellow 5), E110 (sunset yellow, Yellow 6), E104 (quinoline yellow), E122 (carmoisine) and E124 (ponceau 4R). Faced with that label, some manufacturers selling in Europe have reformulated with colors from plants such as paprika and beetroot, so the same branded product can be colored differently in Europe and the US. For the full picture of what is and is not allowed on each side, see food dyes banned in Europe but allowed in the US.

What foods contain Red 40?

The FDA says certified colors are commonly used in cereals, beverages, gelatins, puddings, dairy products, candy, baked goods, snack foods and ice cream. In practice, look closely at:

• Brightly colored breakfast cereals and fruit snacks
• Candy, frosting, sprinkles and cake decorations
• Sports drinks, sodas and powdered drink mixes
• Flavored yogurts, puddings and gelatin desserts
• Chips and snack crackers with red or orange seasoning
• Pastries, cookies and some frozen treats

It also appears in some medicines, vitamins and cosmetics, which this guide does not cover.

What does Red 40 look like on a label?

US law requires certified colors to be listed by name, so Red 40 cannot be hidden behind a vague term. Look for:

• Red 40 or FD&C Red No. 40
• Red 40 Lake (an insoluble form used in coatings and dry products)
• Allura Red AC
• E129 (on imported or European products)

Colors from natural sources, such as beet juice or paprika, are “exempt from certification” and can be listed more generally. The one exception is carmine (cochineal extract), the insect-derived red, which must be named because some people are allergic to it.

What does the research show?

The Southampton study (2007). This randomized, double-blind, placebo-controlled trial, published in The Lancet, gave 153 three-year-olds and 144 eight- and nine-year-olds drinks containing either a dye mixture plus the preservative sodium benzoate, or a placebo. Red 40 (Allura Red) was in one of the two mixtures, “mix B.” The eight- and nine-year-olds showed a small but significant increase in hyperactive behavior with both mixes when the analysis was limited to children who drank most of their drinks. The three-year-olds showed an effect only with the mixture that did not contain Red 40. The authors concluded that the colors, the preservative, or both increased hyperactivity in children in the general population. The study could not show which individual additive was responsible.

What regulators made of it. The European Food Safety Authority judged the evidence limited and did not change the acceptable daily intake for Allura Red of 7 mg per kg of body weight per day. A 2015 EFSA refined exposure assessment found that none of the intake estimates exceeded that level in any population group. The EU added the warning label anyway, as a precaution.

California’s 2021 review. California’s Office of Environmental Health Hazard Assessment (OEHHA) spent two years reviewing seven FDA-approved synthetic dyes, including Red 40. It concluded that synthetic food dyes can cause or worsen hyperactivity and other behavioral problems in some children, and that children differ in their sensitivity. It also argued that federal intake limits rest on decades-old animal studies that were not designed to detect behavioral effects.

The FDA’s position. The FDA’s consumer guidance says the totality of evidence shows most children have no adverse effects from color additives, “but some evidence suggests that certain children may be sensitive to them.”

Gut studies in animals. A 2022 study in mice found that chronic exposure to Allura Red worsened experimental colitis through effects on gut serotonin. The authors note it remains unknown whether this happens in humans.

What is the US doing about Red 40?

• Federal level. In April 2025, HHS and the FDA announced a plan to phase out petroleum-based synthetic dyes. Red 40 is one of six certified colors the FDA is working with industry to eliminate. As of the FDA’s September 2026 update, the target is the end of 2027, and the phase-out is voluntary: Red 40 remains legally approved. The FDA tracks company pledges, and several large manufacturers and retailers have committed to dates in 2026 and 2027.
• California schools. The California School Food Safety Act (AB 2316), signed on September 28, 2024, bars Red 40, Yellow 5, Yellow 6, Blue 1, Blue 2 and Green 3 from food served or sold in public schools, starting December 31, 2027.
• Other states have passed or proposed their own limits, so rules may differ depending on where you live.

How to avoid Red 40

1. Read the ingredient list, not the front of the box. Red 40 must be named, so checking takes a few seconds.
2. Check “natural” and “no artificial colors” claims. Under updated FDA guidance, products colored from natural sources can use “no artificial colors” more freely, but the ingredient list is still the reliable test.
3. Watch the usual categories. Candy, cereal, drinks, frosting and snack foods are where most dyes are found.
4. Color food yourself. Beet juice, raspberry or strawberry powder, and paprika make reds and pinks for frosting and baking.
5. Cook more from scratch. Synthetic dyes are a hallmark of ultra-processed food. Whole foods do not need them.

The bottom line

Red 40 is not a poison, and most people who eat it show no measurable effect. But regulators on both sides of the Atlantic accept that some children may be sensitive. The EU warns parents on the label, and US regulators and companies are moving away from it. Avoiding it is easy and costs you nothing nutritionally, so if you would rather skip it, read the label and choose something else.