Phenylbenzimidazole Sulfonic Acid

INCI: Ensulizole

What is it?

A water-soluble chemical UVB filter used in sunscreens.

What does it do?

According to PubMed, a 2025 case-control study measuring UV filters in follicular fluid found ensulizole was one of four UV filters present at significantly higher concentrations in women with diminished ovarian reserve compared to healthy controls, among a broader finding that cumulative UV-filter exposure correlated with reduced ovarian-reserve biomarkers -- a real systemic-exposure safety signal rather than a skin-specific efficacy or irritancy finding, and the study examined overall UV-filter body burden rather than isolating ensulizole's individual contribution (DOI: https://doi.org/10.1016/j.envint.2025.109573).

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Sources

UV filter exposure and diminished ovarian reserve: a case-control study

Important disclaimer

This page provides general skincare information and is not medical advice, diagnosis or treatment. Ingredient interactions and evidence summaries reflect published, cited sources — not a personal assessment of your skin. For medical skin conditions, rashes, pregnancy/lactation questions or persistent concerns, please consult a licensed dermatologist or HPCSA-registered practitioner.