Ethynylestradiol pronounced /ˌɛθɨnɨlˌiːstrəˈdaɪ. əl/, also ethynyl estradiol (EE), is a derivative of estradiol. Ethynyl estradiol is an orally bio-active estrogen used in almost all modern formulations of combined oral contraceptive pills. It is one of the most commonly used medications. The same contraindications and precautions apply for EE as with other estrogen medications. Estinyl was a preparation of EE alone that was used for the management of menopausal symptoms and female hypogonadism. EE is released into the environment as a xenoestrogen from the urine and feces of people who take it as a medication.