Someone had posted a link on the diet board to an article about oral yohimbine HCL and how much you needed to take to be effective. I'll try to find it; I don't remember the exact formula - I just figured out what I needed. Basically, for my bodyweight, I need to take 12 mg; you're also supposed to take it on an empty stomach and wait 2-3 hours before eating carbs. I don't take it on my carb load days after reading this article.
Another interesting effect of yohimbine is it helps raise your blood pressure. Not good unless you have really low blood pressure, like I do (my last reading a few weeks ago was 90/56). Since I started taking it, I have fewer issues with faintness/dizziness, especially when dieting. I was really bad, especially in the middle of the night when I had to pee - I'd practically pass out every time I stood up.