Age-Associated Thin Hair Displays Molecular, Structural, and Mechanical Characteristic Changes

October 2022 in “ Journal of structural biology ”

F Baltenneck, Gaïanne Genty, Elias Bou Samra, Marina Richena, Duane P. Harland, Stefan Clerens, Emilie Leccia, Mickael Le Balch, J. Doucet, Jean‐François Michelet, S Commo

hair keratins keratin-associated proteins KAPs cuticle layers medullae hair follicle keratins cuticle medulla follicle

Studysummary This study found that age-related hair thinning in Caucasian women over 50 involves significant structural changes within the hair follicle, suggesting an "aged hair program" rather than just producing thinner hairs. Our plain-language summary of this paper — not a Tressless recommendation.

The study investigates the characteristics of age-associated thin hair in Caucasian women over 50 years old. It finds that thin hairs exhibit significant molecular, structural, and mechanical changes compared to thicker hairs. Specifically, thin hairs show imbalanced expressions of hair keratins and keratin-associated proteins (KAPs), a rounder shape, fewer cuticle layers, and reduced medullae frequency. Mechanically, thin hairs are more rigid, less viscous, and have a lower water diffusion coefficient. These changes suggest that hair thinning with age involves a complex "aged hair program" within the hair follicle, rather than merely producing smaller hairs.

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