Mexoryl SX is the trademark name for a unique organic ultraviolet (UV)  filter that protects the skin by absorbing the energy of UV rays. The patent is held by the cosmetics company, L'Oréal, and has been used in their sunscreen formulas since 1993.

     Mexoryl SX includes the compound ecamsule, reportedly one of the most effective UVA filtering ingredients in sunscreens today.  Ecamsule blocks UV wavelengths in the 290–400 nanometer range, making it the only compound known to protect against all UVA rays and some UVB rays.

     For many years, UVB rays have been recognized as the main culprit in sunburn. UVA rays are a deeper penetrating radiation and there is a suspected link between UVA exposure and longer-term effects such as wrinkles, premature skin aging, reduced elasticity, basal and squamous cell cancers and melanoma.

     On July 24, 2006, the U. S. Food and Drug Administration approved Mexoryl SX. It will reportedly be sold as a daily moisturizer cream and should be on pharmacy shelves sometime this fall.