Artificial additives
Blue 1 (brilliant blue)
Definition
What it is
Artificial synthetic dye: linked to hyperactivity in children; requires mandatory warning label in the EU. The FDA is currently reviewing authorization following California's 2023 ban of several dyes in school foods.
On the label
How it appears on labels
- blue 1
- blue no. 1
- brilliant blue
- e133
Regulation
Regulatory status
- European Union Warning label required
- Japan Restricted
- United States Restricted
Explainer
In plain language
Blue 1, also called Brilliant Blue FCF or E133, is a synthetic food dye made from petroleum-derived raw materials. Its only job is color, giving foods and drinks a bright blue or, when mixed with yellow dyes, a green shade. It is one of the artificial colors approved for food use in the US.
Assessment
Why it is flagged
Blue 1 was among the synthetic dyes examined in the broader debate over food coloring and children's behavior, including the group of dyes covered by the EU's child-activity warning requirement. Products in the EU containing Blue 1 must carry the label 'may have an adverse effect on activity and attention in children', which grew out of the 2007 Southampton study on dye mixtures. California's 2023 school food law restricts several synthetic dyes, and the FDA has faced pressure to re-examine its dye authorizations. The behavioral evidence is a group-level association seen in some children rather than an established effect for everyone, and EFSA's review kept Blue 1 authorized with an acceptable daily intake. Clear Label flags it for transparency so families can test whether it tracks with anything in their own logs.
In the aisle
Where it commonly shows up
- Blue and green candy and gummies
- Sports drinks and flavored waters
- Frostings and cake decorations
- Ice pops and frozen treats
- Blue or green breakfast cereals
- Some mouthwashes and chewable medicines
Practical
Reading the label
US labels list it as Blue 1, Blue No. 1, FD&C Blue No. 1, or Brilliant Blue. In the EU it is E133. It also appears in foods that are not obviously blue, such as green-colored products and some brown or purple blends where dyes are combined.
Alternatives
If you want to avoid it
Some people choose products colored with spirulina extract, which gives a natural blue, or foods without added color at all. Comparing a candy or drink brand's label often reveals a version that uses plant-based colors instead.
FAQ
Common questions
Does Blue 1 require a warning label?
In the EU, most foods containing Blue 1 (E133) must carry the notice that it may affect activity and attention in children. US labels do not carry that warning, which is why the same product can differ between markets.
Is Blue 1 banned in the US?
No. Blue 1 remains authorized by the FDA as of 2026. California's 2023 law restricts several dyes in foods served in schools, and there is ongoing pressure to review dye authorizations, but Blue 1 is still permitted nationally.
Does it affect every child?
No. The behavioral evidence behind the EU warning was seen in some children within dye mixtures, and individual sensitivity varies. Logging foods and behavior over time is the honest way to see whether it matters in your household.
Citations
Sources
Citation
Primary reference
About this page: the definition, label names, severity, and regulatory chips come from the clearlabel ingredient taxonomy, the same data the scanner uses to score products. Research summaries describe associations reported in published studies, not diagnoses; individual responses vary. Scan any product with clearlabel to see which of its ingredients carry flags.