Ethinyl estradiol is a synthetic derivative of the natural estrogen estradiol. It is one of two estrogens currently used in oral contraceptive pills. The other, mestranol, is converted to ethinyl estradiol before it is biologically active. Ethinyl estradiol and norethindrone are used together as an oral contraceptive agent. Estrogens diffuse into their target cells and interact with a protein receptor. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. This cascade is initiated by initially binding to the estrogen receptors. The combination of an estrogen with a progestin suppresses the hypothalamic-pituitary system, decreasing the secretion of gonadotropin-releasing hormone (GnRH). Used for treatment of moderate to severe vasomotor symptoms associated with the menopause, female hypogonadism, prostatic carcinoma-palliative therapy of advanced disease, breast cancer, as an oral contraceptive, and as emergency contraceptive.

Norelgestromin, the progestin, is the active metabolite of norgestimate and is structurally related to 19-nortestosterone. Norgestimate and norelgestromin mimic the physiologic effects of progesterone at the progesterone receptor. Johnson & Johnson developed an adhesive female contraceptive patch that contains ethinylestradiol (0.75mg) and the progestogen norelgestromin (6mg). his product is a combination contraceptive acting via the inhibition gonadotropins. Its primary mechanism of action involves the suppression of ovulation, including changes in the cervical mucus and endometrium. The patch delivers a continuous flow of hormones through the skin and into the bloodstream. The contraceptive patch is available in countries worldwide.