The antifungal action of dandruff shampoos

The disease commonly known as “dandruff” is caused by numerous host factors in conjunction with the normal flora yeast Malassezia furfur (Pityrosporumovale). Indeed, clinical studies have shown that administration of antifungal agents correlates with an improved clinical condition. Almost all commercially available hair shampoos publicize that they contain some form of antifungal agent(s). However, few studies have been published in which antifungal activity of commercially available hair shampoos have been contrasted experimentally. In this study six commercially available shampoos (in the Philippines) were assessed for antifungal activity against a human (dandruff) isolate of M. furfur: (a) Head & Shoulders (Proctor & Gamble); (b) Gard Violet (Colgate-Palmolive); (c) Nizoral 1% (Janssen); (d)Nizoral 2% (Janssen); (e) Pantene Blue (Proctor & Gamble); and (f) Selsun Blue (Abbott). The results demonstrated that all six of the assayed hair shampoos have some antifungal effect on the test yeast. However, there was consider variation in potency of antifungal activity. Nizoral 1% and Nizoral 2% shampoo preparations were the most effective. The 1% Nizoral shampoo was consistently 10X better at killing yeast cells than the next closest rival shampoo. The 2% Nizoral shampoo was 10X better than the Nizoral 1% product and 100 times better than any of the other products assayed. The study demonstrated that shampoos containing a proven antifungal compound were the most effective in controlling the causative yeast. This revised version was published online in June 2006 with corrections to the Cover Date.