In addition, we have unexpectedly found that after using the hair diameter increasing agent for about 6 months in accordance with the process of the present invention, the diameter of the hair shafts in the treated area increased by up to a percentage of about 50 percent. Similarly, we have found that the oiliness of these treated areas also decreased by about 9% during this period. In view of these results, we have discovered a correlation between sebum excretion rate and hair diameter, i.e. that those who experienced a greater than 20% increase in hair diameter also experience about a 6% decrease in sebum excretion rate. Conversely, those who did not use the hair diameter increasing agent and who experienced about a 5% decrease in hair diameter also had about a 20% increase in scalp oiliness. We believe that the use of products which are capable of reducing the oil of the treated area, e.g. scalp, will also enhance the thickness of hair when used on a regular basis.
EXAMPLES
The following shampoos were used in the Examples below:
Shampoo A: a 1% ketoconazole shampoo available from Neutrogena Corporation under the tradename, "Long Lasting Dandruff Shampoo."
Shampoo B: a 1% zinc pyrithione shampoo available from the Procter & Gamble Company under the tradename, "New Head & Shoulders."
The following test methods were performed in the Examples below:
1) Pilary Index (% .mu.m): The pilary index was calculated as the product of the percent of anagen hair and the hair shaft diameter (.mu.m).
For the baseline assessment, hair samples were identified on the vertex area then plucked out with a rubber-tipped tweezer. The removed hair sample was placed under a microscope in order to count the hair strands and to identify the hair cycle stage for each respective strand, i.e. anagen (growing), telogen (ending), or catagen (resting). From these resulting trichograms the proportion of hairs in the anagen phase was obtained.
A computerized image analysis of the same hair samples was performed using a MOP Videoplan analyzer manufactured by Kontron GmbH in order to measure the average diameter of the hair shafts in accordance with the directions provided therewith.
By using a 3-point midline and facial coordinate system with nose tip, ear and fontanelle coordinates, precise relocation of the sample site was achieved for measurements taken after the baseline assessment.
2) Hair shedding: The amount of hairs shed was evaluated by a semi-luantitative count of the hairs collected immediately after the last shampoo usage by the subject, which typically was about 24 hours before a subject visited the laboratory for evaluation. The hairs were collected in a small transparent envelope and then compared with a series of similar reference envelopes kept at the laboratory. Each reference envelope contained a multiple of 10 hairs. The number of hairs shed in the subject's envelope was matched to a reference standard.
3) Sebum excretion (.mu.g/cm.sup.2 /hour): A sample site near the hairline was located using the above 3-point midline and facial coordinate system. One hour after cleaning the skin of the site with a 70% ethanol solution, the amount of sebum excreted at that area was measured by holding a probe of a computerized Model SM810 Courage sebumeter from Khazaka, (GmbH to the site until an excretion value was provided on the sebumeter.
Using the above-mentioned 3-point system, precise relocation of the sample site was achieved for measurements taken after the baseline assessment.
Example 1
Comparative Testing: Percent Hairs in Anagen Phase
Forty-four adult males who ranged in age from 18 to 65 years old, had mild to moderate dandruff, and had mild androgenic alopecia of the vertex, were assigned to shampoo 2 to 3 times per week with Shampoo A, and forty-three other males having the same characteristics were similarly assigned to shampoo with Shampoo B. Before beginning to shampoo with their assigned shampoo, the baseline pilary index value was calculated for each male. After 6 months of shampooing according to this regime, the pilary index value for each male was recalculated.
As evidenced in Table 1 below and in FIG. 1, both the ketoconazole-containing shampoo and the zinc pyrithione-containing shampoo beneficially improved the percent of anagen hairs by 8.3% and 10.3%, respectively.
