I went 2.5 years without noticing symptoms. I started realizing something was strange when the cramps and tingling started. I figured moodiness, exhaustion and brain fog was par for the course for having 3 kids. Once I had the mirena removed for the cramps (and tingling, but no doc believes that it's related) I felt better within a week. Energy up, mood up, libido up. Besides the incessant tinging in my left arm and leg, I feel pretty much back to my old self! So I guess what I'm saying is I didn't have any side effects until two and a half years down the line, but in retrospect, I really did have symptoms all along, but was hard to tell as I was already exhausted since I was only 6 weeks post partem when I had it in. The exhaustion just lasted a lot longer than it should have.