⚠️ Safety Verdict: Caution Advised for Children
E133 (Brilliant Blue) is approved but requires a warning label in the EU: "may have an adverse effect on activity and attention in children." It's one of the "Southampton Six" colours linked to hyperactivity. Consider avoiding for children, especially those with ADHD or behavioural concerns.
🚸 EU Warning Label Required
Products containing E133 in the UK/EU must display: "May have an adverse effect on activity and attention in children"
This warning exists because of the 2007 Southampton Study linking artificial colours to hyperactivity.
What is E133 (Brilliant Blue)?
E133 is Brilliant Blue FCF, a synthetic blue dye derived from petroleum (coal tar). It's also known as:
- FD&C Blue No. 1 (US name)
- CI 42090 (colour index)
- Blue 1
How it works:
- Creates a bright blue colour
- Often mixed with E102 (Tartrazine) to make green
- Very stable – doesn't fade easily
- Water-soluble – dissolves in drinks and water-based foods
Where is E133 Found?
Common Foods:
- Blue sweets – Smarties, M&Ms, jelly beans
- Sports drinks – blue-coloured energy drinks
- Ice cream and ice lollies
- Cake decorations and icing
- Tinned peas – added to make them appear greener
- Blue cocktails and mixers
- Breakfast cereals – coloured pieces
Non-Food Products:
- Medicines – coloured pills and liquids
- Mouthwash
- Shampoos and soaps
- Cosmetics
Health Concerns
1. Hyperactivity in Children (Southampton Study)
The 2007 Southampton Study found that mixtures of artificial colours (including E133) plus sodium benzoate increased hyperactivity in children:
- Study included 3-year-olds and 8-9 year olds
- Children showed increased hyperactive behaviour when consuming the colour mixture
- Led to EU requiring warning labels
- Some UK manufacturers removed artificial colours voluntarily
💡 The "Southampton Six"
E133 is one of six colours studied. The others are: E102 (Tartrazine), E104 (Quinoline Yellow), E110 (Sunset Yellow), E122 (Carmoisine), and E129 (Allura Red). All require the same warning label.
2. Allergic Reactions (Rare)
- Cross-reactivity with aspirin in sensitive individuals
- Skin reactions – urticaria (hives) reported
- Asthma symptoms in very sensitive people
3. Gut Absorption
- E133 is poorly absorbed – mostly passes through
- Small amounts may be absorbed and excreted in urine (can turn urine blue!)
- No evidence of accumulation in body
Regulatory Status
UK/EU: Approved with ADI of 6mg per kg body weight, but requires warning label
US: FDA approved (FD&C Blue No. 1) – no warning required
Australia: Approved (Code 133)
Who Should Avoid E133?
🚫 Consider Avoiding:
- Children – especially those with ADHD or hyperactivity
- People with aspirin sensitivity – potential cross-reaction
- Those with allergies to azo dyes
- Parents following precautionary approach
✅ Lower Risk:
- Most adults tolerate E133 without issues
- Occasional consumption unlikely to cause problems
The Bottom Line
- ⚠️ Linked to hyperactivity in children (Southampton Study)
- ⚠️ Warning label required in UK/EU products
- ⚠️ Synthetic petroleum-derived dye
- ✅ Generally safe for most adults in small amounts
- ✅ Poorly absorbed – mostly passes through body
- 💡 Natural alternatives exist – spirulina, butterfly pea flower
Our recommendation: Consider avoiding E133 for children, particularly those with behavioural concerns. For adults, occasional consumption is unlikely to cause problems, but choosing products with natural colours is a reasonable precautionary approach.
Last updated: February 2026