Terephthalylidene Dicamphor Sulfonic Acid

Ecamsule is a UV-A absorber (290–400 nm) patented by L'Oreal. It is derived from benzylidene camphor, making it highly photostable.

Ecamsule is able to prevent UV from reaching the skin. It absorbs UV and releases it as thermal energy.

It does this by:

1. Converting an isomer using light via a process called photoisomerization.
2. Using light energy to excite the molecules and release the energy via photoexcitation.

The pH of ecamsule needs to be neutralized due to it being an acid. Triethanolamine is a pH adjusting ingredient often used with ecamsule.

This sunscreen ingredient is approved for use in the EU, Canada, and Asia. In the US, you will only find this ingredient in select L'Oreal products.