4-(Phenylazo)resorcinol
Caution
CAS Number: 2051-85-6
About 4-(Phenylazo)resorcinol
An azo dye used as a semi-permanent hair and cosmetic colorant with EU restrictions due to concerns about reductive cleavage to aromatic amines.
Detailed Analysis
4-(Phenylazo)resorcinol (Resorcinol Violet) is an azo dye combining resorcinol with a phenylazo group. It is used as a direct dye in semi-permanent hair coloration and cosmetic products. The EU has restricted this substance under Regulation 1223/2009, requiring specific labeling and conditions of use due to the potential for reductive cleavage of the azo bond, releasing aromatic amines that may be carcinogenic. It remains permitted in hair dye formulations under specific restrictions.
Skin Benefits
- ✓ Provides violet-purple direct dye coloration
- ✓ Used in semi-permanent hair color formulations
Known Concerns
- ⚠ EU restricted hair dye substance
- ⚠ Azo bond - potential for reductive cleavage to aromatic amines
- ⚠ Skin sensitization risk
- ⚠ Must not be used for eyebrows and eyelashes in EU
Safety Score
Caution
Based on EU regulatory data, published safety research, and ingredient function analysis.
References
EU CosIng Database
European Commission cosmetic ingredient registry
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