Safety Information


The FDA reviewed the safety of ensulizole and approved its use as an active ingredient in OTC sunscreen products. 

Sunscreens are regulated by the FDA as non-prescription, OTC drugs. 

In February 2019, the FDA published a proposed rule requesting additional data on certain currently used sunscreen ingredients, including ensulizole. 

Importantly, FDA emphasized in a Sept. 27, 2021, announcement that sunscreens made with these ingredients are not considered unsafe and will remain on the market to be used as part of consumers’ sun-safe practices while more data are collected. 

According to the FDA, “Sun safety is important for everyone and all skin tones, and consumers can reduce risks from sun exposure with continued use of sun protection measures, including sunscreen.” 

These filters are approved around the globe and have been used in various formulations in the U.S. for decades.

The Personal Care Products Council (PCPC) and its member companies that manufacture sunscreen products have been working closely with the FDA to collect additional data that will address FDA’s request.

Expert Panel for Cosmetic Ingredient Safety

The Expert Panel for Cosmetic Ingredient Safety (Expert Panel) has deferred evaluation of this ingredient because the safety has been assessed by the FDA. This deferral follows the Expert Panel’s procedures

Ensulizole and its potassium, sodium and TEA salts are listed in Annex VI, entry 6 (which specifies the UV filters cosmetics products may contain ) of the Cosmetics Regulation of the European Union. It may be used in sunscreen products.

The European Commission’s Scientific Committee on Consumer Products (SCCP) reviewed the safety of ensulizole and its potassium, sodium and TEA salts, concluding that the use of these ingredients in cosmetics products at a maximum concentration of 8% would not pose a risk to human health.

Phenylbenzimidazole sulfonic acid is approved as a safe and effective sunscreen ingredient in Australia, Canada and in Japan.



What Is It?

Ensulizole (also known as phenylbenzimidazole sulfonic acid) is a white to pale beige powder. Potassium phenylbenzimidazole sulfonate, sodium phenylbenzimidazole sulfonate and triethanolamine (TEA)-phenylbenzimidazole sulfonate are salts of ensulizole. It is also used as an active ingredient in over-the-counter (OTC) sunscreens products.

Why Is It Used?

Ensulizole is approved by the U.S Food and Drug Administration (FDA) for use as a sunscreen agent in products that are applied to the skin to absorb, reflect or scatter UV rays. In addition to ensulizole, its potassium, sodium and TEA salts are also permitted to be used in sunscreens products in the European Union.

When ensulizole or its salts are applied to the skin, these ingredients absorb ultraviolet (UV) rays. Exposing unprotected skin to UV light can result in sunburn (primarily from UVB rays) and promote premature aging of the skin, as well as skin cancer (primarily from UVA rays).

Scientific Facts

Ensulizole and its salts have the ability to convert UV radiation into less damaging infrared radiation (heat).