Sulfates are the main circulating conjugates of ethinyl estradiol and glucuronides predominate in urine. The first oxidative metabolite is two-hydroxy ethinyl estradiol, shaped by the CYP3A4 isoform of cytochrome P450. Element of the 1st-move metabolism of ethinyl estradiol is thought to take place in gastrointestinal mucosa. Ethinyl estradiol may