Science
Mechanism of Action
This compound functions by undergoing oxidation reactions within the hair shaft, forming colored complexes characteristic of p-phenylenediamine derivatives, thereby imparting permanent color. Scientific research has not identified any mechanism of action that confers benefits to the skin.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
This ingredient's primary function is as an oxidation dye for hair. It is not an active ingredient for skincare and therefore not subject to typical 'dusting' considerations for dermal efficacy.
The Formula
Formulation
Stability
The core p-Phenylenediamine structure is stable, but sensitive to oxidation upon air exposure, leading to discoloration from white to purple/black. It is also chemically sensitive to light and moisture, requiring storage under an inert atmosphere below +30°C.
Conflicts
- Oxidizing agents
- Isocyanates
- Halogenated organics
- Peroxides
- Acidic phenols
- Epoxides
- Anhydrides
- Acid halides
- Iron oxides
Safety
Safety Profile
The CIR Expert Panel deems p-Phenylenediamine (and its salts) safe for hair dye applications up to 2.5%. However, it is explicitly considered unsafe for dermal coloring applications (e.g., temporary black henna tattoos) and for use in eyelash and eyebrow dyes due to high irritation potential and sensitization risk. In the US, it is unapproved for dermal coloring and eye makeup.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Due to its primary role as a hair dye, lack of skin benefits, high irritancy, and explicit safety restrictions for dermal contact, this ingredient is unsuitable for precision skincare formulations.
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