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Restricted hair dye

HC BLUE NO. 4

CAS 158571-57-4
25

Safety score · 0–100

Caution

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

HC Blue No. 4 is a nitro-type hair dye whose EU evaluations raised genotoxicity and impurity concerns. Its allowed use is narrow and any broader cosmetic application is not acceptable.

Skin benefits

  • Provides a blue shade in semi-permanent hair dyes
  • Used historically to extend hair color palettes

Known concerns

  • SCCS evaluations flagged genotoxicity and impurity concerns
  • Use heavily restricted or under prohibition in EU Annex II or III
  • Skin sensitization potential typical of nitro hair dyes
  • Not suitable for general cosmetic use beyond strictly limited hair coloring

References

EU

EU CosIng database

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

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Same plant / compound family

35
HC BLUE NO. 10
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HC BLUE NO. 11
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HC BLUE NO. 12
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HC BLUE NO. 13
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HC BLUE NO. 14
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HC BLUE NO. 15
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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.