dunno, I've read a few threads regarding that kind of stuff before.
Often people need to leave the stuff on them for a bit (like 5-10min) for the hair to dissolve properly and for some people it irritates the skin.
It also comes back pretty fast since it does't do anything to the hair beyond skin level so once the hair grows a bit again it visible above skin level again.
Some say it works good since they just sorta shower w/ the stuff.
The first time will take the longest for it to dissolve so even if you are one of those that need to let it sit to work you may be able to maintaine w/ the shower method.
As for myself never used it since I havn't the need.