Zoely is a combined oral contraceptive pill that is used to prevent pregnancy. It contains two active ingredients, nomegestrol acetate, a progestogen, and estradiol, a form of estrogen. These hormones work together to inhibit ovulation, alter the cervical mucus to prevent sperm from reaching the egg, and change the lining of the uterus to prevent attachment of a fertilized egg. Zoely is known for having a 24 active pill and 4 inactive pill regimen, which is slightly different from the traditional 21 active and 7 inactive pill regimen found in many other birth control pills. This regimen is designed to closely mimic the natural menstrual cycle, potentially resulting in fewer hormonal fluctuations and side effects for some users. Zoely is also noted for containing estradiol, which is identical to the estrogen produced by the ovaries, rather than the synthetic estrogen (ethinylestradiol) found in many other contraceptive pills.