E133 — Brilliant blue FCF
E133 (Brilliant blue FCF), a color, is rated "avoid": worth avoiding. A vivid blue synthetic dye in candy, drinks, and ice cream. It carries no EU children's warning and the behavioural evidence is weaker than for the yellow and red dyes — but it is a petroleum-derived colour with thin long-term data, and both the FDA and California have now moved to get it out of food.
What is Brilliant blue FCF?
A vivid blue synthetic dye made from petroleum, common in candy, sports drinks, ice cream, mouthwash, and toothpaste. Also called FD&C Blue No. 1. Like every colouring, it exists to make the product look more appealing and does nothing for taste or nutrition.
What does it do to the body?
Very little is absorbed from the gut; most passes straight through, and the direct behavioural evidence in children is genuinely weaker than for the Southampton dyes — we won't pretend otherwise. California's health hazard office nonetheless grouped it with the colours it found can cause or exacerbate neurobehavioural problems in some children, drawing on animal and mechanistic data. There are isolated reports of skin reactions, and blue discoloration after very large doses in tube-feeding. Children are the heaviest consumers and the reason for the caution.
What regulators say
EU labels do not require the hyperactivity warning for this dye — that applies to six other colours, not this one — and EFSA raised its acceptable daily intake to 6 mg per kg of body weight per day in 2010. The FDA still permits it as Blue 1, last reviewing it in 1969, but in April 2025 asked manufacturers to remove it voluntarily by the end of 2026; California bans it from school food from the end of 2027.
Risk rating: Avoid
Known or suspected to cause harm: a substance EFSA or another regulator has flagged, or one restricted in some jurisdictions. Best kept out of a regular diet.
Source: OEHHA (California EPA) — Potential Neurobehavioral Effects of Synthetic Food Dyes in Children (2021) ↗