I don't have any scientific proof other than my own experience but would recommend people are very cautious with nizoral. I started using it and got a bit carried away with the instant thickening effect it had. After using it every day/other day for about 2-3 weeks I am pretty sure it has caused me to shed a huge amount of hair from the top of my head. I have lost hair from parts of the scalp I my male pattern baldness wasn't affecting.