Changes in Structure and Geometric Properties of Human Hair by Aging

July 2010 in “ International Journal of Cosmetic Science ”

Shinobu Nagase, Yoshio Kajiura, Akira Mamada, Hiroko Abe, Satoshi Shibuichi, Naoki Satoh, Takashi Itou, Yuya Shinohara, Yoshihito Amemiya

hair luster hair diameter hair cross-section ellipticity hair fiber curvature synchrotron radiation microbeam X-ray diffraction microstructure lateral distribution misalignment of hair fibers

Studysummary This study found that hair luster decreases with age in Japanese females, primarily due to an irregular increase in fiber curvature which affects hair alignment.

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In a study involving 230 Japanese females aged between 10 and 70 years, researchers investigated the effects of aging on hair properties from macroscopic to microscopic levels. They found that hair luster, as perceived through sensory tests, decreases with age. However, changes in hair diameter and the ellipticity of the hair cross-section were not sufficient to explain the reduction in luster due to aging. The study identified that an irregular increase in hair fiber curvature with age contributes to the loss of luster. Detailed structural analysis using synchrotron radiation microbeam X-ray diffraction showed that the inhomogeneity in the hair's microstructure lateral distribution increased with age, which is associated with the irregular curvature increase. This curvature leads to misalignment of hair fibers, resulting in reduced luster and contributing to the appearance of aging hair.

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Changes in Structure and Geometric Properties of Human Hair by Aging

Research cited in this study

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