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Colorant

DIRECT BLACK 51

CAS 3442-21-5 Updated
20

Safety score · 0–100

Caution

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

About

A black disazo direct dye for hair color. Azo dyes can split into aromatic amines, some of which are listed carcinogens. EWG considers it unacceptable for verified-clean products.

Function

HAIR DYEING

Skin benefits

  • Provides deep black hair-dye color
  • Direct dye does not need oxidation
  • High tinctorial strength

Known concerns

  • Disazo dye with cleavable aromatic amines
  • EWG flags as unacceptable for verified products
  • Potential carcinogen breakdown products

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.