The process where thick terminal hairs become progressively finer, shorter and lighter.
Miniaturisation is the hallmark process in androgenetic alopecia. Affected follicles do not disappear overnight. Instead, repeated hair cycles produce progressively smaller hairs, so scalp coverage falls even if the number of follicles has not dramatically changed. On trichoscopy, miniaturisation appears as hair shaft diameter diversity: some hairs are thick and terminal, while others are thin and vellus-like. This helps distinguish pattern hair loss from simple shedding. Treatments such as finasteride, dutasteride and minoxidil aim to slow miniaturisation, prolong growth, or improve follicle output.
British Association of Dermatologists: Hair loss male pattern (androgenetic alopecia) — https://www.bad.org.uk/pils/hair-loss-male-pattern-androgenetic-alopecia; DermNet: Trichoscopy of generalised noncicatricial hair loss — https://dermnetnz.org/topics/trichoscopy-of-generalised-noncicatricial-hair-loss; Anastassakis K. Androgenetic Alopecia From A to Z, Vol. 1, Springer, 2022 — https://doi.org/10.1007/978-3-030-76111-0
