Testosterone (T) and 17β-estradiol (E$_2$) are produced in both male and female humans and play crucial roles in metabolic regulation. As production decreases with aging, metabolic dysfunction and degenerative diseases develop. This article discusses the shared benefits of E$_2$ and T for metabolic function in both sexes. In females, E$_2$ is essential for bone and vascular health, subcutaneous adipose tissue distribution, skeletal muscle insulin sensitivity, anti-inflammatory immune function, and mitochondrial health. T also plays a role in female skeletal, vascular, and metabolic health, converting to E$_2$ to prevent excess visceral adiposity and promote insulin sensitivity via estrogen receptors. In males, T's conversion to E$_2$ is fundamental to bone and vascular health, and it prevents excess visceral adiposity and promotes insulin sensitivity via androgen receptors. Optimizing levels of both hormones may be beneficial for protecting patients from cardiometabolic disease and frailty during aging, but further research is needed.Testosterone (T) and 17β-estradiol (E$_2$) are produced in both male and female humans and play crucial roles in metabolic regulation. As production decreases with aging, metabolic dysfunction and degenerative diseases develop. This article discusses the shared benefits of E$_2$ and T for metabolic function in both sexes. In females, E$_2$ is essential for bone and vascular health, subcutaneous adipose tissue distribution, skeletal muscle insulin sensitivity, anti-inflammatory immune function, and mitochondrial health. T also plays a role in female skeletal, vascular, and metabolic health, converting to E$_2$ to prevent excess visceral adiposity and promote insulin sensitivity via estrogen receptors. In males, T's conversion to E$_2$ is fundamental to bone and vascular health, and it prevents excess visceral adiposity and promotes insulin sensitivity via androgen receptors. Optimizing levels of both hormones may be beneficial for protecting patients from cardiometabolic disease and frailty during aging, but further research is needed.