Science
Mechanism of Action
This active ingredient operates as a selective UV-B filter, absorbing radiation primarily within the 280-320 nm range, with peak efficiency observed at 306 nm. Upon absorbing UV energy, it undergoes a transformation that converts this energy into heat or longer, harmless wavelengths. This creates an imperceptible protective layer on the skin's surface, preventing UV-induced cellular damage, mitigating sunburn, and reducing the risks of photoaging and skin cancer.
Research
Clinical Evidence
High confidenceRegulatory maximums for its use as a UV filter range from 3% in Japan to 8% (as the acid) in the EU and Canada, with 4% permitted in the USA, China, and India.
Key findings
- 01 Regulatory approvals by FDA (USA)
- 02 EU Cosmetics Regulation
- 03 Japan regulations
- 04 China and India regulations
Transparency
Dusting Analysis
The Formula
Formulation
Stability
As a potassium salt, this ingredient is highly water-soluble. Formulations achieve optimal stability within a pH range of 6.0 to 7.0. To prevent recrystallization of the parent acid, it is generally recommended to maintain a pH above 6.8, although stabilization using basic amino acids can extend the lower pH limit to 6.0 without compromising integrity.
Safety
Safety Profile
Generally recognized as safe for cosmetic and sunscreen applications when incorporated at recommended concentrations. However, some individuals, especially those with sensitive skin, may experience localized irritation, manifesting as redness, itching, or a burning sensation upon application. Allergic reactions, while reported, are rare. Its parent compound, Ensulizole (Phenylbenzimidazole Sulfonic Acid), received FDA approval in the USA in 1999 and is permitted up to 8% (as the acid) in the EU.
Your Skin
Skin Compatibility
Our Assessment
Verdict
This water-soluble UV-B filter effectively protects against sunburn and photoaging, making it a valuable component in broad-spectrum sun protection formulations.
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