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Moumoujus

2-AMINO-5-ETHYLPHENOL HCL.

Avoid CAS 149861-22-3 / HAIR DYEING

A synthetic aromatic amine compound primarily developed as an oxidative hair dye coupler that forms permanent color through chemical reactions with oxidizing agents. This ingredient has demonstrated significant safety concerns including skin sensitization potential and barrier disruption properties. While effective for its intended hair coloring applications, its safety profile makes it unsuitable for precision skincare formulations.

Summary

hair dyeing color coupling agent

Science

Mechanism of Action

Functions as a reactive coupling agent that undergoes oxidative polymerization reactions with developers like p-phenylenediamine in the presence of hydrogen peroxide, forming large chromophore molecules that provide permanent coloration within hair structures

Research

Clinical Evidence

High confidence
Effective range ≤1.5%
Optimal

N/A

Key findings

  1. 01 European safety assessment identified genotoxicity concerns and confirmed skin sensitization potential in oxidative hair dye applications
  2. 02 Direct application caused severe skin barrier compromise, reducing trans-epidermal resistance from >10 kΩ to 3.7 kΩ within 24 hours

Transparency

Dusting Analysis

Not commonly dusted
Red flag below
0.1%

This ingredient should be considered a red flag at any concentration in skincare due to confirmed skin sensitization and genotoxicity concerns identified by European safety authorities

The Formula

Formulation

Solubility
Water
Optimal pH 9 – 10.5
0 7 14

Stability

Maintains chemical integrity for minimum 7 days at ambient temperature with less than 10% deviation, but requires highly alkaline conditions for optimal reactivity

Conflicts

  • Strong oxidizing agents
  • Excessive alkaline conditions
  • Metal catalysts (iron, copper salts)

Safety

Safety Profile

CIR Status
Not reviewed
Max tested
1.5%
Pregnancy
Caution
Sensitization risk High

European Commission safety assessment confirmed skin sensitization potential and raised genotoxicity concerns regarding metabolite formation, leading to regulatory restrictions even in hair dye applications

Your Skin

Skin Compatibility

No Normal
No Dry
No Oily
No Sensitive
Irritancy High
Comedogenicity Unknown

Our Assessment

Verdict

Avoid

This hair dye ingredient presents significant safety concerns including confirmed skin sensitization and barrier damage, making it inappropriate for precision skincare applications.

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