Science
Mechanism of Action
This direct, non-reactive dye binds to substrates like skin proteins through ionic interactions. Its action is optimized under acidic conditions (pH 2.0-4.0), coating surfaces without significant deep penetration.
Research
Clinical Evidence
Medium confidence0.5%
Key findings
- 01 At 0.5% concentration, dermal absorption was approximately 0.25 µg/cm² in porcine skin, indicating low systemic exposure and safety in non-oxidative hair dye formulations (SCCS/1536/14).
- 02 Evaluation at 0.8% in oxidative conditions showed low dermal absorption, though full safety conclusions were pending due to unknown stability (SCCS/1536/14).
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Highly stable in acidic aqueous solutions (pH 2.0-4.0) for at least 72 hours. Stability is significantly reduced in oxidative environments, such as those containing hydrogen peroxide.
Conflicts
- strong oxidizing agents
- strong reducing agents
- oxidative environments
Safety
Safety Profile
SCCS deems it safe up to 0.5% in non-oxidative hair dyes. The EU restricts its use in all cosmetics, specifically prohibiting application in the eye area.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Acid Orange 7 is a valuable colorant for topical cosmetic applications (excluding the eye area) due to its low dermal absorption and established safety profile at concentrations up to 0.5% in acidic formulations.
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References
Sources