Table 2.

Harmful effects of testosterone in COVID-19.

References	Study type	Findings
Stopsack et al. (2020)	Systematic review	Testosterone promotes expression of the TMPRSS2.
Cao et al. (2017)	Experimental study	Testosterone therapy increases the expression of CD147.
Montopoli et al. (2020)	Population-based study	Androgen deprivation therapy reduces COVID-19 severity.
Adamowicz et al. (2020)	Observational study	High dihydrotestosterone level is linked to poor pulmonary outcomes in COVID-19 patients.
McCoy et al. (2020)	Observational study	5-α reductase inhibitors is associated with good clinical outcomes in COVID-19 patients.
Wambier et al. (2020)	Observational study	Low androgen sensitivity is linked to low COVID-19 mortality.
Wang et al. (2020); Bwire (2020)	In vitro and review studies	Circulating testosterone has immunosuppressive effects.
Mishra et al. (2019)	Experimental study	Testosterone has a permissive effect for circulating AngII by expressing AT1R and downregulation of ATR2 with a higher ATR1R/AT2R ratio.
Blauschmidt et al. (2017)	Case-series study	Testosterone upregulates the expression of DPP4 receptors.