Science
Mechanism of Action
Functions as a coupling agent in oxidative hair dye systems, where the formyl-pyrazolone ring structure undergoes condensation reactions with primary intermediates under alkaline conditions to generate high-molecular-weight pigment molecules that become trapped within the hair shaft
Research
Clinical Evidence
High confidence0.25%
Key findings
- 01 Demonstrated safety with exceptional margin of 66,670 based on 0.08% dermal absorption in oxidative hair dye systems
- 02 No dermal irritation or significant sensitization observed in clinical diagnostic testing
Transparency
Dusting Analysis
Regulated ingredient with established maximum concentrations; exceeding 0.5% in finished products would violate EU cosmetic regulations
The Formula
Formulation
Stability
Maintains stability in alkaline environments but degrades above 161°C; light-sensitive requiring amber packaging and preferably inert atmosphere storage
Synergies
- hydrogen peroxide
- p-phenylenediamine developers
Conflicts
- strong oxidizing agents
- primary amines
- strong acids
Safety
Safety Profile
EU Cosmetics Regulation Annex III compliant; maximum 0.5% in finished products yielding 0.25% upon dilution with peroxide; prohibited for eye area use
Our Assessment
Verdict
Specialized hair dye ingredient with excellent safety profile but limited to specific oxidative coloring applications rather than general skincare.
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References
Sources