Estradiol salicylate, or estradiol 3-salicylate, is a synthetic estrogen and estrogen ester â specifically, the C3 salicylic acid ester of estradiol â which was described in the late 1980s and was never marketed. It is a metabolite of estradiol acetylsalicylate, which appears to be very rapidly hydrolyzed into estradiol salicylate.