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Azo colorant (Sudan III / Solvent Red 23)

1-(4-(Phenylazo)phenylazo)-2-naphthol

CAS 85-86-9
22

Safety score · 0–100

Caution

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

An azo dye known as Sudan III or Solvent Red 23 used historically as a deep red colorant. Regulators flag carcinogenicity, mutagenicity, and skin sensitization concerns, with significant restrictions on cosmetic use.

Skin benefits

  • Historically used as a deep red dye for industrial and certain cosmetic colorant applications
  • Provides intense color at low concentration

Known concerns

  • Suspected carcinogen (H351); IARC-related cleavage product 4-aminoazobenzene is Group 2B
  • Genotoxicity concern (H341 suspected mutagen)
  • Causes skin and eye irritation and may cause allergic skin reaction
  • Restricted in EU cosmetics; banned around eyes and on mucous membranes
  • Listed on Canada Cosmetic Hotlist with significant safety restrictions

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, so always read the physical product label and consult a healthcare professional for personal concerns.