 [ Symptoms ] how long does a girl need to be on the pill in order to safely have unprotected sex [ Disease ] depending on the pill it is generally recommended you be on the pill for a full month before you consider it completely effective if you have any questions about this consult your pharmacist remember that the pill only protects you against unwanted pregnancy it does not protect you against sexually transmitted diseases for this reason it is still important to practice safe sex with a condom wishing you all the best