Not to be picky, but are you referring to NIZORAL?
The box says to use it 2-3 times a week for the first week and then use it once per week to maintain, but that is for dandruff treatment.
I use Nizoral to rid my scalp of excess DHT, and in some cases people have claimed that it can act similar to Rogaine. Mild regrowth and a healthier scalp.
I shampoo with it at least three times a week and leave it on the scalp for at least 3-5 minutes before rinsing. Some people use more but I've found good results in slowing my hairloss with this treament, as well as using all natural shampoos and a conditioner with hemp oil.