Science
Mechanism of Action
Functions through dual pathways: as a direct dye, its compact molecular structure enables diffusion into hair cuticles, while in oxidative systems it acts as a coupler, reacting with aromatic amines in the presence of hydrogen peroxide to create larger, stable pigment molecules that become trapped within the hair matrix.
Research
Clinical Evidence
High confidence0.5%
Key findings
- 01 SCCP 2006 assessment demonstrated Margin of Exposure of 357 at 0.5% concentration with NOAEL of 15 mg/kg bw/d
- 02 CIR repeated insult patch testing on 206 subjects at 0.1-0.2% showed no adverse irritation
- 03 2024 dermal penetration studies confirmed systemic absorption of 0.83 ± 0.69 µg eq/cm² at 0.2-0.29%
Transparency
Dusting Analysis
Regulated ingredient with established maximum concentrations; presence above 0.5% would indicate non-compliance with European safety standards
The Formula
Formulation
Stability
Maintains stability under standard conditions but exhibits photosensitivity requiring light protection; sulfate salt enhances water solubility compared to free base form
Synergies
- hydrogen peroxide
- aromatic amines
- aqueous alcoholic solutions
Conflicts
- strong oxidizing agents
- strong acids
- strong reducing agents
- acid chlorides
- acid anhydrides
Safety
Safety Profile
European Annex III restricts maximum hair application to 0.5% post-oxidative mixing; classified as known skin sensitizer requiring appropriate precautions
Your Skin
Skin Compatibility
Our Assessment
Verdict
While technically safe at regulated concentrations for hair applications, its high sensitization potential and specialized hair-dyeing function make it unsuitable for precision skincare formulations.
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