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Naphthalene-1,5-diol and its salts

CAS 83-56-7
45

Safety score · 0–100

Moderate

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

About

Naphthalene-1,5-diol And Its Salts is a cosmetic ingredient. Exercise caution due to limited available safety data.

Naphthalene-1,5-diol (CAS 83-56-7) functions as a coupler in oxidative hair dyeing to develop brown coloration when combined with appropriate primary intermediates. EU Regulation 1223/2009 Annex III restricts its maximum concentration to 1.0% in hair dye products. The compound carries hazard statements H302 (harmful if swallowed), H317 (may cause allergic skin reaction), H319 (causes serious eye irritation), and H411 (toxic to aquatic life with long lasting effects). The naphthalene structure and hydroxyl groups contribute to its moderate sensitization potential and environmental concern.

Skin benefits

  • Used as coupling agent for brown shades in hair dyes
  • Provides natural-looking color development
  • Works with various primary intermediates

Known concerns

  • Maximum 1.0% concentration limit in EU hair dyes
  • Skin sensitizer (H317)
  • Eye irritation hazard (H319)
  • Aquatic toxicity (H411)
  • Oral toxicity concern (H302)

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.