A study investigated the association between circulating sex hormones and disease severity in patients with COVID-19. The research found that lower testosterone levels were linked to more severe illness in men, while estradiol and IGF-1 levels were not significantly associated with disease severity in men. In women, no significant differences in hormone levels were observed between those with severe and mild disease. Testosterone concentrations were inversely associated with inflammatory markers such as IL-6, CRP, and HGF in men. Gene expression analysis revealed upregulated hormone signaling pathways in monocytes of men with severe COVID-19 requiring ICU treatment. The study suggests that low testosterone may contribute to worse outcomes in men with COVID-19, highlighting the need for further research to confirm this mechanism. The findings indicate that testosterone levels could be a marker for disease severity, but the study could not determine whether testosterone is a mediator or a marker. The study also found no significant changes in estradiol levels in patients with COVID-19. The results suggest caution in approaches that antagonize testosterone signaling or supplement estrogen in men with severe COVID-19. The study was conducted on 152 patients, with 143 hospitalized, and included data on hormone levels and inflammatory markers. The study highlights the importance of considering sex differences in the pathophysiology of COVID-19.A study investigated the association between circulating sex hormones and disease severity in patients with COVID-19. The research found that lower testosterone levels were linked to more severe illness in men, while estradiol and IGF-1 levels were not significantly associated with disease severity in men. In women, no significant differences in hormone levels were observed between those with severe and mild disease. Testosterone concentrations were inversely associated with inflammatory markers such as IL-6, CRP, and HGF in men. Gene expression analysis revealed upregulated hormone signaling pathways in monocytes of men with severe COVID-19 requiring ICU treatment. The study suggests that low testosterone may contribute to worse outcomes in men with COVID-19, highlighting the need for further research to confirm this mechanism. The findings indicate that testosterone levels could be a marker for disease severity, but the study could not determine whether testosterone is a mediator or a marker. The study also found no significant changes in estradiol levels in patients with COVID-19. The results suggest caution in approaches that antagonize testosterone signaling or supplement estrogen in men with severe COVID-19. The study was conducted on 152 patients, with 143 hospitalized, and included data on hormone levels and inflammatory markers. The study highlights the importance of considering sex differences in the pathophysiology of COVID-19.