Estradiol sulfate
As the sodium salt, sodium estradiol sulfate, E2S is present as a minor constituent (0.9%) of conjugated equine estrogens (CEEs), or Premarin. It effectively functions as a prodrug to estradiol in this preparation, similarly to E1S. E2S is also formed as a metabolite of estradiol, as well as of estrone and E1S. Aside from its presence in CEEs, E2S is not available as a commercial pharmaceutical drug.
Mestranol
Mestranol was employed as the estrogen component in many of the first oral contraceptives, such as mestranol/noretynodrel (brand name "Enovid") and mestranol/norethisterone (brand names "Ortho-Novum", "Norinyl"), and is still in use today. In addition to its use as an oral contraceptive, mestranol has been used as a component of menopausal hormone therapy for the treatment of menopausal symptoms.