If you switch birth controls how long will it take for them to kick in?

The new Birth Control method may be immediately effective, or there may be a delay, depending on the change. For instance, if changing from the pill, patch, ring or shot to the pill, patch, ring or shot, you have immediate protection as long as you aren't starting the new method later than you were supposed to start the next cycle of the old one. Talk to your health care provider for advice specific to your situation.