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Moumoujus

HC RED NO. 1.

Avoid CAS 2784-89-6 / HAIR DYEING

HC Red No. 1 is an aromatic direct dye, known chemically as 4-amino-2-nitrodiphenylamine, primarily utilized in semi-permanent hair coloring systems. This low molecular weight compound functions by penetrating the hair shaft to impart color, with research indicating poor percutaneous absorption through human cadaver skin.

Summary

Hair Dyeing

Science

Mechanism of Action

As a direct dye, HC Red No. 1 operates by depositing pigment directly onto the hair shaft, negating the need for an oxidative process to achieve coloration. Its molecular structure allows for efficient penetration into the hair fiber, providing temporary coloring, while its limited transdermal absorption minimizes systemic exposure.

Research

Clinical Evidence

High confidence
Effective range N/A
Optimal

N/A

Transparency

Dusting Analysis

Not commonly dusted

HC Red No. 1 is primarily a hair dye ingredient and is not associated with exaggerated claims or 'dusting' within the skincare industry.

The Formula

Formulation

Solubility
Unknown
Optimal pH N/A
0 7 14

Safety

Safety Profile

CIR Status
Safe with restrictions
Max tested
0.5%
Sensitization risk High

The Cosmetic Ingredient Review (CIR) Expert Panel deemed HC Red No. 1 safe in hair dye applications at concentrations of 0.5% or below. While not identified as a dermal irritant, it is classified as a mild ocular irritant and a robust contact sensitizer, with strong evidence suggesting it acts as a human skin toxicant or allergen. There is limited evidence of carcinogenicity. The Scientific Committee on Consumer Safety (SCCS) permits its use in non-oxidative hair dye formulations up to 1.0%.

Your Skin

Skin Compatibility

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

Our Assessment

Verdict

Avoid

Given its primary role as a hair dye and significant potential for skin sensitization and allergenicity, HC Red No. 1 is not suitable for inclusion in precision skincare formulations.

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