Skip to content

Colorant

BASIC YELLOW 40

CAS 29556-33-0 Updated
50

Safety score · 0–100

Moderate

Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.

About

A cationic (basic) yellow hair dye in the methine class — EU-restricted to specific maximum levels in oxidative and non-oxidative hair-colour products. Documented sensitizer, requires patch testing.

Skin benefits

  • Vibrant yellow shade for hair dye formulas
  • Effective at low concentrations

Known concerns

  • Documented skin sensitizer in cationic hair dye class
  • Concerns about systemic absorption from scalp
  • Photosensitization risk at high levels
  • EU Annex III-restricted hair dye

References

EU

EU CosIng database

European Commission cosmetic ingredient registry — regulatory status, restrictions, authorised functions.

Related colorants

50
1H-Indene-1,3(2H)-dione, 2-(2-quinolinyl)-, sulfonated, sodium salts (CI 47005)
Colorant
 50
ACID BLUE 62
Colorant
 50
ACID RED 184
Colorant
 50
ACID RED 33
Colorant
 50
ACID VIOLET 43
Colorant
 50
BASIC RED 76
Colorant
 50
BROMOTHYMOL BLUE
Colorant
 50
CI 12370
Colorant

Check your shelf

Find BASIC YELLOW 40 in your products.

Scan any cosmetic product with LuxSense to see if it contains BASIC YELLOW 40 and get a full ingredient breakdown with safety scores.

This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve — always read the physical product label and consult a healthcare professional for personal concerns.