It definitely works. At least for me. Though it is hard to rate how effective it is. It is more of a subtle feeling of calmness and often my heart rate goes down a bit too. I think 500 mg is a pretty good dose and I usually take it on such a time in the day so it is right before I have to do something I find anxiety inducing. Combined with the medications I'm on it adds to the calmness.
Make it so number one. Engage!