Science
Mechanism of Action
Functions as a dye precursor that penetrates hair fibers and undergoes oxidative coupling reactions with other precursors to form permanent color molecules within the hair structure
Research
Clinical Evidence
High confidence0.049%
Key findings
- 01 Repeated insult patch testing on 206 volunteers at 0.049% showed no irritation or sensitization reactions
- 02 Guinea pig studies at 3% demonstrated significant sensitization potential (90% reaction rate)
- 03 Rabbit studies showed concentration-dependent irritation: non-irritating at 2.5%, slight irritation at 5%
Transparency
Dusting Analysis
Restricted ingredient with specific regulatory limits; not applicable for general skincare formulations
The Formula
Formulation
Stability
Dihydrochloride salt form enhances water solubility compared to base compound. Requires protection from heat, light, and moisture due to oxidation sensitivity. Best incorporated into shampoo-based systems or oxidative dye creams.
Conflicts
- Strong oxidizing agents (except controlled hair dye reactions)
- Strong acids
- Heavy metal ions
Safety
Safety Profile
CIR and SCCS approve use only in oxidative hair dyes up to 0.5% on-head concentration. Recognized as potential human sensitizer. Prohibited in general skincare applications and restricted under EU Annex III.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Restricted hair dye ingredient with significant sensitization potential that is inappropriate for precision skincare formulations.
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References
Sources