TMPRSS2 and androgenetic alopecia: Conversely, to date, the only known regulators of TMPRSS2 expression are androgens, which may explain the prevailing presence of males in severe COVID-19, in particular those with androgenetic alopecia (AGA), in which TMPRSS2 expressed seems to be more expressed than in non-AGA males, due to increased hyperandrogenic hormones, specially 5-alpha dihydrotestosterone (5alpha-DHT), enhanced androgen receptor sensibility, or both [8, 9].