Science
Mechanism of Action
As an oxidative hair dye precursor, M-Phenylenediamine Sulfate's primary mechanism involves participating in a chemical reaction within permanent hair coloring systems. When exposed to an oxidizer like hydrogen peroxide, it forms reactive intermediates that subsequently combine with other couplers. This reaction generates complex color molecules that embed themselves within the hair fiber, providing durable color. It does not exert a direct beneficial cosmetic effect on the skin; rather, its interaction is with the hair shaft.
Research
Clinical Evidence
Insufficient-data confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
The base chemical, m-Phenylenediamine, is susceptible to oxidation upon air exposure, leading to color changes (red/purple). While optimal pH for cosmetic stability isn't explicitly stated, analytical measurements suggest stability in acidic conditions (pH 3 or lower).
Conflicts
- Strong oxidizers (e.g., chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine)
- Alkaline materials, strong bases
- Strong acids, oxoacids
- Epoxides, acid chlorides, acid anhydrides, chloroformates
- Metals
Safety
Safety Profile
The CIR Expert Panel deemed it safe for use in hair dyes at concentrations up to 10%, but explicitly unsafe for direct dermal applications like temporary tattoos or for eyelash/eyebrow dyes. It is prohibited in cosmetics in Australia, listed in Annex II of the EU Cosmetics Directive (meaning it cannot be used), and will be banned in California effective January 1, 2025, due to associated health risks. It has been noted to cause skin irritation and sensitization.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Due to significant regulatory bans in major markets and documented risks of skin irritation and sensitization, M-Phenylenediamine Sulfate is not suitable for cosmetic formulations intended for skin contact.
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References
Sources