DermNet provides Google Translate, a free machine translation service. Note that this may not provide an exact translation in all languages


Allergy to ensulizole

Author: Vanessa Ngan, Staff Writer, 2012.


What is ensulizole and where is it found?

Ensulizole, also known as phenylbenzimidazole sulfonic acid, is a chemical substance that is used in sunscreen products. It is able to absorb the full spectrum of UVB rays but provides little protection against UVA rays. It is usually formulated with other sunscreen agents, particularly UVA chemical absorbers such as avobenzone, ecamsule and bemotrizinol. It is also often paired with the metal oxides, titanium dioxide and zinc oxide to achieve a sunscreen product with coverage against both UVA and UVB rays.

Unlike other chemical absorbers, ensulizole is water soluble and is used in products formulated to be less oily and feel lighter on the skin. Hence it is often used in cosmetic moisturisers, with a sunscreen component, for daily use.

What are the reactions to ensulizole allergy?

Because ensulizole is relatively new to the sunscreen market there are few reports or studies available documenting its adverse effects and long term use.

Alternative names for ecamsule

  • Phenylbenzimidazole sulfonic acid
  • 2-phenyl-3H-benzimidazole-5-sulfonic acid

Further information

Formula: C13H10N2O3S

CAS number: 27503-81-7

Cross reactions: unknown



  • Book: Photoaging. Ed Rigel DS, Weiss RA, Lim HW, Dover JS. Marcel Dekker, Inc 2004

On DermNet

Other websites

Books about skin diseases


Related information

Sign up to the newsletter