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Hair dye precursor

P-AMINOPHENOL HCL

CAS 51-78-5
30

Safety score · 0–100

Caution

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

An aromatic aminophenol used as an oxidative hair dye precursor for dark shades. Carries mutagenicity and aquatic toxicity flags and is tightly restricted under EU cosmetics rules.

Skin benefits

  • Oxidative hair dye precursor producing deep brown to black shades
  • Combines with couplers to expand permanent hair color palette

Known concerns

  • GHS H302 harmful if swallowed and H332 harmful if inhaled
  • H341 suspected of causing genetic defects (mutagenicity)
  • H400/H410 very toxic to aquatic life with long-lasting effects
  • Strong skin sensitizer; restricted to maximum 0.9 percent in oxidative hair dye under EU Annex III

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.