I had the testing done. I can't say as I've "used" it very much as I have terrible heath coverage so I have to stick to inexpensive drugs unless the doc could give me samples. We did use it in terms of avoiding the things that said I wouldn't metabolize very well. It also showed that the drugs that had helped me in the past were "good" ones for me so there was that synergy. I think it's still a fairly controversial idea; people are divided about it's worth/not (what else is new?)