Science
Mechanism of Action
Functions as a reactive precursor that penetrates the hair cuticle and chemically bonds with primary intermediates in the presence of hydrogen peroxide, forming large chromophore molecules that become permanently trapped within the hair shaft structure
Research
Clinical Evidence
High confidence1.5%
Key findings
- 01 CIR 2023 assessment demonstrated extremely low percutaneous penetration at 1.0% in oxidative systems
- 02 SCCP evaluation confirmed safety profile at maximum 1.5% concentration in final hair dye mixtures
Transparency
Dusting Analysis
Not applicable for skincare formulations as this ingredient is exclusively designed for hair coloration applications
The Formula
Formulation
Stability
Demonstrates superior stability in oxidative environments when mixed with hydrogen peroxide. HCl salt form provides enhanced aqueous solubility compared to free base. Typically formulated at alkaline pH 8.0-10.0 for optimal hair cuticle swelling
Synergies
- p-phenylenediamines
- hydrogen peroxide oxidizing systems
Conflicts
- Strong reducing agents
- Non-intended oxidizing agents outside color development systems
Safety
Safety Profile
EU Annex III restricted to maximum 1.5% in final hair application mixtures. Presents as severe eye irritant when undiluted, but 5% aqueous solutions show good tolerance profiles
Your Skin
Skin Compatibility
Our Assessment
Verdict
Specialized hair dye ingredient with no established skincare applications or benefits for facial formulations.
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References
Sources