Everybody is different.. My head is shaved to number 1.. so it takes around 2 weeks.. I wash my hair twice a day with it. This is the only shampoo that I am using right now.
I use Nizoral 2% 5-7 times per week and for me a 100ml lasts about 2 months (rough estimate). I use 2% Nizoral cream whenever I don't wash my hair with Nizoral to make sure that I receive my daily dose of Ketoconazole