Nizoral anti-dandruff shampoo is the 13th best selling product on Amazon.com this week. But at about $17 for 7 ounces it’s significantly more expensive than Head and Shoulders and other dandruff products. Why is that?     Nizoral Ingredients Here are the ingredients according to Drugstore.com (Amazon doesn’t list them!) Active ingredient: Ketoconazole, 1% Inactive [...]