Estrone Sulfate
Estrone sulfate (E1-S) is a sulfate derivative of estrone, and is the most abundant form of circulating estrogens in both men and non-pregnant women.
Estrone sulfate itself does not have direct estrogenic activity, it may be considered rather as a slowly-metabolized estrogen reservoir. The determination of estrone sulfate, as a marker of global estrogenic activity, can be used for monitoring of hormone replacement therapy in postmenopausal women.