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BENZOIN ETHYL ETHER.

Avoid CAS 574-09-4 / FILM FORMING

A high-performance Norrish Type I photoinitiator primarily utilized to catalyze the rapid polymerization of UV-curable resins. While essential in specialized medical and nail applications, its role in traditional skincare is limited to fragrance masking and structural curing rather than direct biological benefit.

photoinitiator masking fragrance

Science

Upon exposure to UV radiation in the 330–340 nm range, the molecule undergoes homolytic alpha-cleavage. This process generates reactive benzoyl and alpha-ethoxybenzyl radicals which initiate the cross-linking of unsaturated monomers, effectively transforming liquid formulations into durable, solid polymer matrices.


Research

Medium confidence
Effective range 1–5%
Optimal

3%

Key findings

  1. 01 Evaluated as an effective catalyst in UV-curable nail gels for controlled drug release, demonstrating high reactivity and stability.
  2. 02 Demonstrated curing speeds 2.5 times faster than standard benzoin in medical-grade methacrylate systems.

Transparency

Not commonly dusted
Min. effective
1%
Red flag below
0.5%

As a reactive photoinitiator, concentrations below 1% in UV-cured systems may result in incomplete polymerization, while its use in leave-on skincare at any level is often purely for masking purposes and lacks therapeutic justification.


The Formula

Solubility
Oil
Optimal pH N/A
0 7 14

Stability

Highly light-sensitive; must be stored in opaque or amber containers to prevent premature activation. Stable at room temperature when shielded from UV exposure.

Synergies

  • Unsaturated monomers
  • Methacrylate-based oligomers

Conflicts

  • Strong oxidizing agents
  • Strong acids
  • Atmospheric oxygen
  • UV light

Safety

CIR Status
Not reviewed
Max tested
5%
Sensitization risk High

Classified as a Category 1 Skin Sensitizer (H317). It is known to cause allergic reactions upon contact and is toxic to aquatic ecosystems.


Your Skin

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

Our Assessment

Avoid

While technically proficient as a photoinitiator for nail and dental hardware, its high sensitization risk and lack of skin-active benefits make it unsuitable for precision leave-on skincare.


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