Mestranol is a synthetic estrogen used primarily in hormonal contraceptives. It is often combined with progestins to create oral birth control pills, helping to prevent ovulation and regulate menstrual cycles. Mestranol is converted into ethinyl estradiol in the body, which is the active form that exerts its effects. In addition to contraception, mestranol may be used in hormone replacement therapy for menopausal symptoms. It can also help manage certain menstrual disorders. As with any medication, it is important to discuss potential side effects and risks with a healthcare provider before use.