Estropipate, also known as piperazine estrone sulfate and sold under the brand names Harmogen, Improvera, Ogen, Ortho-Est, and Sulestrex among others, is an estrogen medication which is used mainly in menopausal hormone therapy in the treatment of menopausal symptoms. It is a salt of estrone sulfate and piperazine, and is transformed into estrone and estradiol in the body. It is taken by mouth.

Estropipate is used to:^{[additional citation(s) needed]}

Estropipate was available in the form of 0.75, 1.5, 3, and 6 mg oral tablets and 1.5 mg/gram vaginal cream. Estropipate is no longer available in the United States.

Estropipate is a prodrug of estrone and estradiol. Hence, it is an estrogen, or an agonist of the estrogen receptors.

Estropipate is hydrolyzed into estrone in the body. Estrone can then be transformed into estradiol by 17β-hydroxysteroid dehydrogenase.

Estropipate was introduced for medical use by Abbott in 1968. It was approved by the FDATooltip Food and Drug Administration in the United States in 1991.

Estropipate is the generic name of the drug and its INNTooltip International Nonproprietary Name, USANTooltip United States Adopted Name, and BANTooltip British Approved Name.

Estropipate was marketed under the brand names Genoral, Harmogen, Improvera, Ogen, Ortho-Est, and Sulestrex among others.