Estradiol disulfate (also known as E2DS or estradiol 3,17β-disulfate) is an endogenous estrogen conjugate and metabolite of estradiol. It is related to estradiol 3-sulfate and estradiol 17β-sulfate. Estradiol disulfate has 0.0004% of the relative binding affinity of estradiol for the estrogen receptor alpha (ERα), one of the two estrogen receptors (ERs).[1]