Ensulizole

Ensulizole, also known as 2-phenylbenzimidazole-5-sulfonic acid, is a water-soluble sunscreen agent that absorbs strongly at UV-B wavelengths. It is commonly found in cosmetic products and sunscreen formulas in combination with other UV filter compounds due to its minimal protection against UV-A wavelengths. Due to its water solubility, ensulizole is commonly used in products formulated to feel light and less oily [A32259]. It was demonstrated by studies that ensulizole treatment provided protection against cyclobutane pyrimidine dimers and photosensitized the formation of oxidized guanine bases after UV-A or UV-B exposure [A27151]. According to the FDA, the maximal approved concentration of ensulizole is 148 mM although concentrations ranging between 74 and 148mM can be found in commercial sunscreen products [A27151].