C. Piérard-Franchimont, V. Goffin, F. Henry, I. Uhoda, C. Braham, G. E. Piérard.
Nudging hair shedding by antidandruff shampoos. A comparison of 1% ketoconazole, 1% piroctone olamine and 1% zinc pyrithione formulations.
International Journal of Cosmetic Science Volume 24, Issue 5, Page 249-256, Oct 2002
Synopsis
Hair shedding and hair thinning have been reported to be affected by dandruff and seborrhoeic dermatitis. The present study was conducted in 150 men presenting with telogen effluvium related to androgenic alopecia associated with dandruff. They were randomly allocated to three groups receiving each one of the three shampoos in the market containing either 1% ketoconazole (KTZ), 1% piroctone olamine (PTO) or 1% zinc pyrithione (ZPT). Shampoos had to be used 23 times a week for 6 months. Hair shedding during shampoo was evaluated semiquantitatively. Hair density on the vertex was evaluated on photographs using a Dermaphot. Trichograms were used for determining the anagen hair percentage and the mean proximal hair shaft diameter using computerized image analysis. The sebum excretion rate (SER, g cm2 h1) was also measured using a Sebumeter®.
The three treatments cleared pruritus and dandruff rapidly. At end point, hair density was unchanged, although hair shedding was decreased (KTZ: -17.3%, PTO: -16.5%, ZPT: -10.1%) and the anagen hair percentage was increased (KTZ: 4.9%, PTO: 7.9%, ZPT: 6.8%). The effect on the mean hair shaft diameter was contrasted between the three groups of volunteers (KTZ: 5.4%, PTO: 7.7%, ZPT: -2.2%). In conclusion, telogen effluvium was controlled by KTZ, PTO and ZPT shampoos at 1% concentration. In addition, KTZ and PTO increased the mean hair shaft thickness while discretely decreasing the sebum output at the skin surface.
From the full study:
Conclusion
The present study comparing 1% KTZ, 1% PTO and 1% ZPT shampoos has demonstrated that these products have some other benefits in addition to their reported antidandruff effect. The data show that these shampoos have a beneficial effect on the anagen/ telogen ratio, by increasing the anagen hair percentage in subjects with dandruff. This results in a reduced hair shedding. In addition, the data show that 1% KTZ and 1% PTO, but not 1% ZPT, produce a beneficial effect on scalp seborrhoea and hair shaft diameter. The reason for such opposite effect is unknown. Finally, the data show that scalp seborrhoea is inversely correlated with hair thickness. The virtue of such a finding is its simplicity. However, the results cannot be taken at face value. There may remain debate whether reducing sebum excess on the scalp may lead to thicker hair, and whether increasing scalp seborrhoea may be accompanied by a reduction in the hair shaft diameter.
