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Moumoujus

BASIC BLUE 41.

Avoid CAS 12270-13-2 / HAIR DYEING

A cationic azo dye primarily utilized as a synthetic colorant in hair care and textile applications. Due to its molecular structure, it provides intense pigmentation but lacks functional benefits for skin health.

Summary

colorant hair dyeing

Science

Mechanism of Action

This ingredient functions via electrostatic attraction; its positively charged molecules bind to negatively charged carboxyl groups within keratin and surface proteins on the skin and hair.

Research

Clinical Evidence

Low confidence
Effective range N/A
Optimal

N/A

Key findings

  1. 01 In vitro testing on HepG2 cells indicated oxidative damage and cytotoxic effects consistent with azo-dye structures.
  2. 02 Toxicological reviews indicate significant risk of conjunctival swelling and corneal damage upon eye contact, alongside persistent skin staining.

Transparency

Dusting Analysis

Not commonly dusted
Red flag below
2%

As a regulated hair dye component, any presence in leave-on skincare is atypical. Concentrations near 2.0% are reserved for hair formulations and require specific safety warnings.

The Formula

Formulation

Solubility
Water
Optimal pH 2.5 – 5
0 7 14

Stability

Exhibits high thermal stability up to 120°C and maintains integrity in acidic environments (pH < 5.0), though color shifts may occur in highly specific acid baths.

Conflicts

  • Anionic surfactants
  • Strong oxidizing agents
  • Strong reducing agents
  • Copper ions
  • Iron ions

Safety

Safety Profile

CIR Status
Not reviewed
Max tested
2%
Sensitization risk High

Classified as a coal tar hair dye derivative; US regulations mandate specific caution statements and patch test instructions for products containing this ingredient.

Your Skin

Skin Compatibility

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

Our Assessment

Verdict

Avoid

Basic Blue 41 is a high-irritancy hair colorant with no documented benefits for skincare and potential for oxidative cellular damage.

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