Winding the clock back on female androgenetic alopecia

Conflicts of interest None declared. Androgenetic alopecia (AGA) describes the replacement of terminal hairs on the frontal and vertex scalp with progressively finer, shorter and nonpigmented vellus hairs. The term AGA emphasizes the hormonal and genetic basis of the patterned hair loss that commonly affects both men and women and increases in frequency and severity with age.1 The androgen‐dependent nature of male pattern hair loss in men was demonstrated in 1942 when Hamilton2 showed that baldness did not develop in 10 eunuchoid men, 10 men castrated before puberty and 34 men who had undergone orchiectomy during adolescence. Administration of testosterone led to the development of common baldness in those individuals who were genetically predisposed. When testosterone was discontinued the baldness did not progress but was not reversed.2 No subsequent investigator has been able to challenge Hamilton’s findings, and it is established beyond doubt that common baldness in men is androgen dependent.