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Allergy to ecamsule

Author: Vanessa Ngan, Staff Writer, 2012.


What is ecamsule and where is it found?

Ecamsule is a benzylidene derivative and is a chemical substance that is used in sunscreen products. It is able to absorb the full spectrum of UVA rays and some UVB rays. It was developed and patented by L’Oreal and approved for use in Europe in 1991. In 2006, the FDA approved its use in the US.

Ecamsule has greater photostability when compared with avobenzone. Although ecamsule does not degrade as quickly as avobenzone when exposed to hours of sun, it does breakdown and lose 40% of its protective properties. To improve its UV coverage and photostability ecamsule has been formulated with avobenzone and octocrylene. This product is marketed in the US as Anthelios SX and some tests show it to be effective in vitro for as much as 5 hours.

What are the adverse reactions to ecamsule?

Because ecamsule is relatively new to the sunscreen market there are no studies available regarding its long term use. Safety and efficacy studies performed for FDA approval showed that ecamsule was well tolerated and any side effects were infrequent and mild. The most common reactions were dermatitis, dry skin, acne, itching, redness and skin discomfort. Further long-term human safety studies are required.

Alternative names for ecamsule

  • Terephthalylidene dicamphor sulfonic acid
  • Mexoryl SX

Further information

Formula: C28H34O8 S2

CAS number: 92761-26-7

Cross reactions: unknown



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

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