Vitex supplement helps fertility!!

I was wondering if there are any women on here who have used Vitex? I personally know two friends who have been married for about 3 years and have been trying to have a baby for about 2 years... One has very irregular periods and they both used Vitex and within 2 months of taking it they were both pregnant and now have healthy babies! I want to try it, but I was wondering if anyone else has used it?