Birth control sprintec, how long does it take to work?

It depends: It depends on when in your cycle you started the pills. If you started on the first day of bleeding, it's effective right away. If later in your cycle, it typically takes 7 days to take effect, so use back up birth control prior to then. It also may depend on when you last had sex, and what you used for protection.

Give it a month: Oral contraceptives scientifically take effect after 4 doses, but, i highly recommend that you use backup (condom) for one cycle to ensure that you taking the pills correctly. Remember, however even with taking them correctly, there is a 2 percent failure rate. Also, they do not stop stds, so if you are at risk, also use condoms to decrease the chance of catching a disease.