TMPRSS2 and androgenetic alopecia: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cell entry and subsequent infectivity are mediated by androgens and the androgen receptors through the regulation of transmembrane protease, serine 2 (TMPRSS2). Androgenetic alopecia (AGA) predisposes males to severe coronavirus disease 2019 (COVID-19) disease, while the use of 5-alpha-reductase inhibitors (5ARis) and androgen receptor antagonists reduce COVID-19 disease severity.