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Benzidine based azo dyes

3

Safety score · 0–100

Avoid

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

About

An entire class of banned dyes derived from the carcinogen benzidine. These can break down to release cancer-causing benzidine on your skin.

Benzidine-based azo dyes are a class of colorants where the dye structure is derived from benzidine (4,4'-diaminobiphenyl). Benzidine is a known human bladder carcinogen, and many benzidine-derived dyes are also considered carcinogenic. The EU Cosmetics Regulation (EC) No 1223/2009 prohibits these substances in cosmetic products, with restrictions listed in Annex II. Azo dyes that can cleave to release benzidine are specifically banned due to their potential to form carcinogenic aromatic amines.

Known concerns

  • Known human carcinogen class
  • EU Annex II banned for cosmetic use
  • Potential to release carcinogenic aromatic amines

References

EU

EU CosIng database

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

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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.