Sulfates are the main circulating conjugates of ethinyl estradiol and glucuronides predominate in urine. The primary oxidative metabolite is two-hydroxy ethinyl estradiol, shaped from the CYP3A4 isoform of cytochrome P450. A part of the main-pass metabolism of ethinyl estradiol is believed to manifest in gastrointestinal mucosa. Ethinyl estradiol m