It has been assumed for years that male testosterone levels play a central role in worsening lipoprotein patterns and causing greater susceptibility to ischemic heart disease. Yet most clinical trials of quasi-physiologic doses of intramuscular testosterone in older men show no effect on high-density lipoprotein (HDL)-cholesterol, while cross-sectional epidemiologic studies almost uniformly find that endogenous testosterone levels are positively associated with HDL-cholesterol levels. Further work is required to determine whether and why physiologic testosterone levels in the high normal range appear to be conducive to optimal cardiovascular health for adult men.