Coronary heart disease is a leading cause of premature death in men. Epidemiological studies have shown a high prevalence of low serum testosterone levels in men with cardiovascular disease. Furthermore, low testosterone is associated in some but not all observational studies with an increase in cardiovascular events and mortality. Testosterone has beneficial effects on several cardiovascular risk factors which include cholesterol, endothelial dysfunction and inflammation; key mediators of atherosclerosis.

A bidirectional relationship between low endogenous testosterone levels and concurrent illness complicate attempts to validate causality in this association and potential mechanistic actions are complex. Testosterone is a vasoactive hormone which predominantly has vasodilatory actions on several vascular beds although some studies report conflicting effects. 

In clinical studies acute and chronic testosterone administration increases coronary artery diameter and flow, improves cardiac ischaemia and symptoms in men with chronic stable angina and reduces peripheral vascular resistance in chronic heart failure. Although the mechanism of action of testosterone on vascular tone in vivo is not understood, laboratory research has found that testosterone is an L-calcium channel blocker and induces potassium channel activation in vascular smooth muscle cells. Animal studies consistently demonstrate that testosterone is atheroprotective whereas testosterone deficiency promotes early stages of atherogenesis. 

Translational effects of testosterone between in vitro, animal and human studies, some of which have conflicting effects, will be discussed. We review the evidence for a role of testosterone in vascular health, its therapeutic potential and safety in hypogonadal men with cardiovascular disease, and some of the possible underlying mechanisms.