Dr Lindsey talks about the green coffee bean on the Dr Oz show in the video below. I believe it would be safe to take for weight loss and I have confidence in Dr Lindsey, however there are two reasons that I would not recommend using green coffee beans to lose weight.
1) It's expensive.
2) You're likely to gain the weight back after you stop taking the product unless you have changed your eating habits during the process.
If you want to try them, I recommend supplementing a healthy diet with green coffee beans occasionally when you are going to be eating a social meal where it might be difficult to make good choices.
Also, some say that green coffee beans leach minerals out of your body. I have not fully researched this tidbit yet but I would encourage you not to take green coffee bean to lose weight because of the reasons I listed, but if you are going to try it anyway, please consider supplementing minerals like calcium, magnesium, and trace minerals.