neil and blackcat, the studies were performed on mice, so there has nbeen no treatment parameter set up for people. It has never been tested on people and is considered experimental.
In the study, it was applied topically, rubbed into the skin. Your guess is as good as mine as far as how much or how long.
Drinking it will not have an effect, although over the course of a lifetime, it appears that soy may have some mild antiandrogenic effects.
So, if you want to try it, I'd probably rub it on my arm for starters, to see if it's sticky or stinky. If it seems OK, I'd try putting it on after a shower and leaving it. If that's not an option, maybe you can put it on in the evening and rinse it off before you go to bed.
Again, it might be as effective as water, but it has shown significant change in hair size and color in mice, which is often a good indication of what might happen in humans.