What Women Want: Quantifying the Perception of Hair Amount - An Analysis of Hair Diameter and Density Changes with Age in Caucasian Women

The study investigated the perception of hair loss in Caucasian women by introducing a new metric called 'hair amount', which combines hair density and diameter. It involved 1099 women with self-perceived hair loss and 315 without, aged 17–86. Measurements showed that hair diameter increased until ages 40-45, then decreased, while hair density was highest at age 20-30 and decreased with age. The 'hair amount' metric remained stable until age 35, then significantly decreased, especially from the mid-40s to late 50s. The study concluded that hair shaft diameter compensates for decreasing hair density until the mid-30s, but after that, both factors contribute to the perception of hair thinning. The 'hair amount' metric is a useful tool for assessing the combined effect of hair density and diameter on the perception of age-related hair loss in Caucasian women.