Red 40, also known as Allura Red AC, is the most widely used artificial food dye in the United States. It’s a synthetic colorant made from petroleum-derived compounds, added to everything from candy and cereal to yogurt and sports drinks to give them a bright red, orange, or berry-toned appearance. While the FDA considers it safe within established limits, it has drawn scrutiny over possible links to hyperactivity in children, and regulators in other countries treat it differently than the U.S. does.
Where You’ll Find It
Red 40 shows up in a surprisingly wide range of products, many of which aren’t even red. It’s blended with other dyes to create purples, browns, and oranges in foods you might not suspect. Common categories include:
- Dairy products: flavored milk, yogurt, pudding, ice cream, and popsicles
- Sweets and baked goods: cakes, pastries, candy, and chewing gum
- Snacks: breakfast cereals, cereal bars, fruit snacks, gelatin desserts, and flavored chips
- Beverages: soda, sports drinks, energy drinks, powdered drink mixes, and some protein powders
It’s also used in cosmetics like lipstick and blush, and in the coatings of many over-the-counter and prescription medications. If a pill or liquid medicine has a reddish or pinkish tint, Red 40 is often the reason.
How to Spot It on a Label
Manufacturers use several names for the same dye. On U.S. ingredient lists, you may see it called Red 40, Red 40 Lake, FD&C Red No. 40, or FD&C Red No. 40 Aluminum Lake. The “Lake” version is a water-insoluble form typically used in products that can’t contain much moisture, like coated tablets or hard candy shells. In Europe and other international markets, it’s listed as E129.
Red 40 and Hyperactivity in Children
The most persistent concern about Red 40 involves children’s behavior. A landmark 2007 trial published in The Lancet tested whether artificial food colors and a common preservative affected hyperactivity in 153 three-year-olds and 144 eight- and nine-year-olds from the general population. Researchers used a randomized, double-blind, placebo-controlled design, meaning neither the children nor the people evaluating their behavior knew who received the dye mixtures and who got a placebo.
The results showed a statistically significant increase in hyperactive behavior in both age groups when they consumed the dye mixtures compared to placebo. Among three-year-olds who drank at least 85% of the test beverages, the effect size was 0.32, a modest but measurable shift. Among the older children, both dye mixtures produced significantly more hyperactive behavior than the placebo. The study concluded that artificial colors or a sodium benzoate preservative, or both together, increased hyperactivity in children in the general population, not just in children already diagnosed with ADHD.
That said, Children’s Hospital of Philadelphia notes that some rigorous studies have not replicated these findings, and the effect sizes in the positive studies are small. Many parents report changes in their children’s focus, irritability, or energy after consuming dyed foods, but controlled research hasn’t consistently confirmed a strong causal link. The overall picture is that some children appear sensitive to these dyes while most are not noticeably affected.
Allergic Reactions and Sensitivities
Despite widespread concern, true allergic reactions to Red 40 are not well documented. Children’s Hospital of Philadelphia reports no confirmed cases of allergic reaction to synthetic red dyes like Red 40. Allergic responses such as hives or tongue swelling have been reported with carmine, a natural red dye derived from insects, but not with Red 40 itself. Some people do report digestive discomfort, headaches, or skin reactions they attribute to the dye, though these individual experiences haven’t been consistently replicated in clinical settings.
How Much Is Considered Safe
The acceptable daily intake for Red 40, established by both the Joint FAO/WHO Expert Committee on Food Additives and the European Food Safety Authority, is 0 to 7 milligrams per kilogram of body weight per day. For a 150-pound adult, that works out to about 477 milligrams daily. For a 50-pound child, the limit is roughly 159 milligrams. These thresholds are based on animal studies that found no adverse effects at doses far below the levels that caused growth suppression in rat offspring (695 mg/kg/day showed no problems; issues appeared at 2,595 mg/kg/day).
Whether typical consumption actually approaches these limits is debated. Children who eat heavily processed diets with brightly colored cereals, snacks, and drinks throughout the day can accumulate more exposure relative to their body weight than adults do.
U.S. vs. European Regulations
Red 40 is approved for use in both the United States and the European Union, but the EU takes a more cautious public-facing approach. Since 2010, any food sold in the EU containing Red 40 or five other synthetic dyes must carry a warning label stating that the colors “may have an adverse effect on activity and attention in children.” This requirement doesn’t ban the dye, but it has pushed many European manufacturers to reformulate their products with natural colorants instead. The same brands often sell dye-free versions of their products in Europe while continuing to use Red 40 in the U.S. market, where no such labeling is required.
Natural Alternatives to Red 40
If you want to avoid Red 40, natural color options exist for both store-bought and homemade foods. Beet juice and beet powder produce reddish-pink tones. Red onion skins yield a reddish-orange. Dried hibiscus flowers create a deep lavender-red. Freeze-dried fruit powders, particularly strawberry and raspberry, can tint frostings, smoothies, and baked goods without synthetic additives. Pre-made plant-based food colorings are available at natural food stores and online, designed as drop-in replacements for artificial dyes in home recipes.
For packaged foods, look for brands that list fruit or vegetable juice concentrates as their coloring agents. Products marketed as “no artificial colors” will use these plant-derived alternatives, though the shades tend to be less vivid and may fade faster than their synthetic counterparts.