The Lab
Specimen No. 0203
CautionSyntheticsunscreen filter

Sulisobenzone

CAS 4065-45-6 · Benzophenone-4 · BP-4 · Sulisobenzone

A water-soluble benzophenone UV filter and UV-absorber that is a recognized contact allergen and for which US regulators have requested more safety data.

high confidence
Researched July 7, 2026

Concerns

  • In North American Contact Dermatitis Group patch testing of 19,618 patients (2013 to 2020), benzophenone-4 (sulisobenzone) produced positive reactions in 1.6 percent, of which 65.8 percent were judged currently clinically relevant, with sources including personal-care products and sunscreens (Warshaw 2023, PMID 36917534)
  • Benzophenone organic UV filters as a class have caused allergic and photoallergic contact dermatitis (Ekstein 2023, PMID 36279254)

Regulatory flags

  • IARC Class: NL
  • EDC Status: Not established
  • Regulatory: US FDA: not classified GRASE, additional safety data requested; EU: permitted UV filter (Annex VI, up to 5%)
  • Evidence Grade: B

Commonly found in

SunscreenHair care with UV filterMakeup with SPFWater-based lotions

Research disclaimer: This rating is based on available peer-reviewed research and regulatory assessments at the time of publication. It is not medical advice. Consult a qualified professional for personal health or skin concerns.

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