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4-METHYLBENZYL 4,5-DIAMINO PYRAZOLE SULFATE.

Questionable CAS 173994-77-9 / HAIR DYEING

A synthetic coal tar derivative primarily engineered as an oxidative hair dye precursor that creates permanent color through chemical reactions within the hair shaft. This water-soluble compound undergoes oxidation to form reactive intermediates that bond with coupling agents, producing stable pigment molecules trapped in keratin structures.

hair dyeing agent oxidative dye precursor

Science

Functions as a primary precursor in oxidative dyeing systems, requiring hydrogen peroxide activation to generate reactive intermediates that combine with coupler molecules like resorcinol to create large, stable chromophores within hair fibers


Research

High confidence
Effective range 0.71–4.8%
Optimal

3%

Key findings

  1. 01 Demonstrated 3-year stability in hair coloring formulations with confirmed safety for topical application
  2. 02 Established effective concentration range for oxidative hair dye systems, with high-concentration products diluted before application

Transparency

Not commonly dusted

Specialized hair dye ingredient with established concentration limits and regulatory oversight, not typically subject to cosmetic dusting practices


The Formula

Solubility
Water
Optimal pH 6.8 – 7.2
0 7 14

Stability

Maintains stability for 36 months at 25°C in cream formulations; requires neutral to slightly alkaline conditions for optimal preservation, though functional use often occurs at pH 9-10

Synergies

  • resorcinol
  • m-aminophenol
  • hydrogen peroxide

Conflicts

  • strong oxidizing agents
  • strong reducing agents
  • nitrosating compounds

Safety

CIR Status
Safe as used
Max tested
4.8%
Sensitization risk High

Classified as coal tar hair dye requiring patch testing protocols and cautionary labeling due to potential for contact sensitization and skin irritation


Your Skin

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

Our Assessment

Questionable

Effective hair dye ingredient with high sensitization potential and no established skincare benefits, unsuitable for precision skincare applications.


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