I don't know what your definition of effective is. Mine is that improves a man's erection. I'm taking 6,000 mg of Source horny goat weed and it works as well as cialis and levitra (which I have personal experience). Yohimbe kicks it up a notch, but it can make you jittery and has other negative health factors. Any marketed herbal pills usually don't have enough of any ingredient to provide anything more than a placebo effect. Before I try anything I research it look at any studies that have been done.