Depo provera (medroxyprogesterone) is good for 3 months but how long does it tske to entirely leave your system? thanks

Good question: Depo-provera has shown diminished fertility for up to one year after the last injection. So clearly it has lasting side effects with your hormonal system. However the drug itself has a short half-life and is out of your system quite quickly after the Depo-Provera dose wears off. So the problem is that it alters your natural hormone balance and it takes a while to recover, not that it's "in your system".