Avobenzone- 13 C,d 3 is the 13 C- and deuterium labeled Avobenzone. Avobenzone, a dibenzoylmethane compound, is one of the most widely used filters in sunscreens for skin photoprotection in the UVA band. Avobenzone is an endocrine disruptor that directly binds to estrogen receptor β and acts as an estrogen agonist.