Avobenzone.

Often referred to by its trade name, Parsol 1789, butyl methoxydibenzoylmethane or Avobenzone, provides superior protection through a large portion UVA range including UVA I.  UVA rays, which contribute to tanning, are most associated with aging the skin. Exposure can promote wrinkling, age spots and loss of elasticity.

It has been widely used in Europe for the last decade. Avobenzone was recently approved by the FDA for use in the U.S. Potentially a significant addition to sunscreen products for true broad-spectrum UV protection, concerns have been raised regarding its photostability and potential to degrade other sunscreen ingredients in products where it is used.

 This is the structure of avobenzone:

Click here for the photochemistry of sunscreens.