Skip to content

UV Filter

3-Imidazol-4-ylacrylic acid (Urocanic acid) and its ethyl ester

CAS 27538-35-8 / 104-98-3
22

Safety score · 0–100

Caution

Derived from EU CosIng regulatory status, PubChem hazard data and published research. How we score.

Urocanic acid (and its ethyl ester) — a UV-absorbing molecule historically used in sunscreens, now restricted/prohibited in EU due to photoallergenic and immunosuppressive effects upon UV conversion to cis-isomer.

Skin benefits

  • UV-absorbing capacity historically used in sunscreens

Known concerns

  • Documented photoallergen
  • Suspected immunosuppressive on UV exposure
  • EU Annex II prohibition for direct cosmetic use
  • Photoreactivity converts trans- to cis- form linked to immune effects
  • No longer approved as UV filter in EU/most regions

References

EU

EU CosIng database

European Commission cosmetic ingredient registry: regulatory status, restrictions, authorised functions.

Related uv filters

Check your shelf

Find 3-Imidazol-4-ylacrylic acid (Urocanic acid) and its ethyl ester in your products.

Scan any cosmetic product with LuxSense to see if it contains 3-Imidazol-4-ylacrylic acid (Urocanic acid) and its ethyl ester and get a full ingredient breakdown with safety scores.

This profile is for educational purposes and does not constitute medical advice. Regulatory status and scientific understanding evolve, so always read the physical product label and consult a healthcare professional for personal concerns.