For me it was around the same time Mo3 mentioned they took, maybe a bit more than one year and a half. It's been long, so I don't remember precisely.

However I was in a quite sorry state before... I was having several panic attacks a week. My therapy alone was also not working well, I was doing twice a week. After starting it, everything started falling into place. I never had a panic attack again.

I never had any downside whatsoever from taking them (didn't know they don't go well with summer!), including the regular complaints, it wasn't really a burden on me other than having to buy them monthly and take them every day.