Performing a standardized 60-second hair count appears to be a reliable method for the assessment of hair shedding, according to a report in the June issue of Archives of Dermatology.

"Currently, there is no widely accepted or standard method for assessing the number of hairs shed daily," according to background information in the article.

The belief that it is normal to shed 100 hairs per day is based on the assumption that the average scalp contains 100,000 hairs, 10% of which are in the telogen (resting) phase. Although this idea is prevalent, it has not been scientifically validated and does not indicate whether shedding remains constant with age or if it is similar between men and women.

Carina A. Wasko, MD, of Baylor College of Medicine, Houston, and colleagues, studied hair loss in 60 healthy men (half of which were 20 to 40 years old and the other half were 41 to 60 years old) without evidence of alopecia (baldness). All the participants were given identical combs and instructions to wash their hair with the same brand of shampoo for three consecutive mornings. On the fourth day, they were asked to comb their hair forward for 60 seconds over a towel or pillowcase of contrasting color before shampooing. The men combed their hair this way and then counted the hairs shed for three consecutive days. This procedure was repeated in eligible participants 6 months later.

The results of the study found that the participants, ages 20 to 40, shed zero to 78 hairs, with an average loss of 10.2 hairs per 60-second test. Men ages 41 to 60 shed zero to 43 hairs, with an average loss of 10.3 hairs per 60-second test. Results were consistent on consecutive days for all participants.

"When repeated six months later in both age groups, the hair counts did not change much," the authors write. "The hair counts were repeated and verified by a trained investigator, with results similar to those of subject hair counts."

The authors conclude that the 60-second hair count is a simple, practical, and objective tool for monitoring conditions associated with hair shedding.

[Archives of Dermatology, June 16, 2008]