Can you say when you started taking it and what dose?
It can take a few days to a few weeks for these meds to start working. I really wish I could give you a definite time. We really all are so different it's just really hard to say.
How long before improvement?
It's really hard to say because we're all different and respond to these meds differently. You could have nausea and a headache for a few days. That was my experience with Lexapro when I first started taking it.