Trying for baby#1 and Letrozole

So me and my husband have been trying for baby #1 for about 6 months now and have had no luck. I finally had a doctors appointment for him to tell me I have a CNS issue that isn't allowing me to ovulate and that I have an alarmly low production of testosterone and estrogen. He wants to put me on Letrozole and I was just curious if any of you ladies have taken it before and how long it normally takes for your body to get adjusted to it?