March 04, 2001 - American Academy of Dermatology Meeting - Washington DC - Scientists working for McNeil, makers of Nizoral anti-dandruff shampoo, presented the findings of a study done on 1% Nizoral shampoo which has good news for hair loss sufferers. It has long been known that 2% prescription Nizoral has beneficial effects on Androgenic Alopecia (MPB). It however has been unclear whether the same benefits can be obtained by using the non-prescription 1% version.

In the study presented (see below), one hundred male volunteers with mild to moderate dandruff and somewhat oily scalp, were using, in a double-blind fashion, either a 1% Nizoral shampoo or a 1% zinc pyrithione shampoo, 2-3 times a week for 6 months.

Analysis of the different parameters set up in the study shows that the hair diameter gradually increased with Nizoral use (+8.46%) over a 6 month period, whereas the diameter showed a trend to decrease with zinc pyrithione use over the same period (-2.28%). The sebum excretion rate was reduced with Nizoral (-6.54%) while it increased with zinc pyrithione (+8.2%) over the same period of time. The number of hair shed over a 24-hour period was reduced by 16.46% with Nizoral and 6.02% with zinc pyrithione after 6 months. Finally, the percentage hairs in anagen phase increased by 6.4% and 8.4% respectively during the study time.

The results are similar to a previous study done on 2% prescription strength Nizoral where it was shown that use of 2% Nizoral yielded a 7% average increase in hair shaft diameter similar to what was achieved by the control group using 2% Minoxidil and a non-medicated shampoo.

So for any hair loss sufferer, this research clearly indicates that using 1% or 2% Nizoral 2-3 times per week, will have positive effects on hair growth as well as controlling dandruff. It is still unclear at this time whether it's the anti-fungal properties or the anti-androgenic properties of Ketokonazole (active ingredient in Nizoral) thats responsible for the hair thickening effects, however because of the decrease in sebum rates as well, it is the authors opinion that the results are due to the anti-androgenic properties of Ketokonazole.

The effects of chronic use of 1% ketoconazole or a 1% zinc pyrithione shampoo on the general health of hair and scalp.

G. Piérard 1and G. Cauwenbergh2
1. Dept Dermatopathology, University of Liège, Belgium; 2. Skin research Center, Johnson &Johnson , Skillman, N.J., USA

Hundred male volunteers with mild to moderate dandruff and somewhat oily scalp, have used, in a double-blind fashion, a 1% ketoconazole shampoo or a 1% zinc pyrithione shampoo. The test shampoos were applied 2 to 3 times weekly for a total period of 6 months. Several parameters that affect the general health of hair and scalp were assessed at start, and after 1, 3 and 6 months. These parameters included the percent of hairs in anagen phase, the diameter of the hairs, sebum excretion rate at the hairline, and the number of hairs shed in the 24-hour period prior to each assessment. At the end of the study, the participants were asked to complete a questionnaire regarding the cosmetic acceptability of the test shampoos.

Forty-four ketoconazole users and forty-three zinc pyrithione users completed the 6 month study period. Analysis of the different parameters shows that the hair diameter gradually increases with chronic ketoconazole use (+8.46%) over a 6 month period, whereas the diameter shows a trend to decrease with zinc pyrithione use over the same period (-2.28%). The sebum excretion rate is reduced with ketoconazole (-6.54%) while it increases with zinc pyrithione (+8.2%) over the same period of time. The number of hair shed over a 24-hour period is reduced by 16.46% with ketoconazole and 6.02% with zinc pyrithione after 6 months. Finally, the percentage hairs in anagen phase increased by 6.4% and 8.4% respectively during the study time. Except for the percentage of hairs in anagen, which showed no difference between the two groups, all other parameters were significantly different in favor of the ketoconazole shampoo.

Both shampoos have been shown to be good anti-dandruff ingredients. Assessment of parameters than can affect the health of hair and scalp, suggests that both ingredients show distinct differences in the way they affect the scalp; indicating that ketoconazole increases hair diameter and reduces scalp oil, whereas zinc pyrithione seems to yield opposite effects. This suggests that, besides their effect on the lipophilic yeast Malassezia spp, ketoconazole and zinc pyrithione act though quite different mechanisms. An overall analysis of hair diameter changes as a function of changes in sebum excretion rate suggests that a reduction in scalp oiliness seems to result in an increased hair diameter. This suggests that, in people with oily hair, regular use of ketoconazole shampoo may result in overall hair fullness.