The instructions say to use it twice a week and to leave in on the hair for 3 minutes before washing off. Do you think that leaving it on for longer (say 10 minutes) and/or using it more times a week might increase its effectiveness?

I have no idea if leaving it on for longer has any additional benefit, but if the manufacturer suggests that 3 minutes is enough for effective absorption, then 3 minutes is probably enough. I wouldn't use it too many times per week because of the potential for scalp irritation.

There are only a couple of small studies on ketoconazole as an agent for treating hair loss, I wouldn't expect too much from it - it's just a helpful little adjunct to finasteride and minoxidil.

thanks, I'll stick to what I do with Nizorelle then. The Nizoral sounded a bit too strong