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.
Estradiol cypionate
Estradiol cypionate, sold under the brand name Depo-Estradiol among others, is an estrogen medication which is used in hormone therapy for menopausal symptoms and low estrogen levels in women, in hormone therapy for transgender women, and in hormonal birth control for women. It is given by injection into muscle once every 1 to 4 weeks.
Side effects of estradiol cypionate include breast tenderness, breast enlargement, nausea, headache, and fluid retention. Estradiol cypionate is a synthetic estrogen and hence is an agonist of the estrogen receptor (ER), the biological target of estrogens like estradiol. Estradiol cypionate is an estrogen ester and a long-lasting prodrug of estradiol in the body. Because of this, it is considered to be a natural and bioidentical form of estrogen.
Estradiol cypionate was first described as well as introduced for medical use in 1952. Along with estradiol valerate, it is one of the most commonly used esters of estradiol. Estradiol cypionate has mostly been used in the United States, but is also marketed in a few other countries. It is not currently available as a generic medication in the United States.