17β Dihydroequilin

17β-Dihydroequilin, or β-dihydroequilin, also known as 7-dehydro-17β-estradiol, as well as estra-1,3,5(10),7-tetraen-3,17β-diol, is a naturally occurring steroidal estrogen found in horses that is closely related to equilin, equilenin, and estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent (1.7%) of conjugated equine estrogens (Premarin).