Findings from a review and meta-analysis of observational studies found an increased risk of death during at least five years of follow-up among men with low levels of testosterone, which is the primary male hormone. The meta-analysis, reported May 14, 2024, in the Annals of Internal Medicine¹ reviewed 11 studies that included 24,109 men.

Men with low testosterone levels (less than 213 ng/dL), low levels of the hormone estradiol (less than 5.1 pmol/L) or high luteinizing hormone levels (greater than 10 IU/L) had an increased risk of all-cause mortality during a follow-up period of at least five years.

And men with very low testosterone levels (less than 153 ng/dL) had a greater risk of cardiovascular disease mortality in comparison with those who had higher testosterone levels.

Researchers also measured sex hormone-biding globulin (SHBG) levels, which binds testosterone. They found that subjects among the lowest 20% had a 15% lower risk of mortality during follow-up and a 19% lower risk of dying from cardiovascular disease compared with men whose levels were among the top 20%. Lower SHBG means more free, active testosterone, while higher SHBG results in less free testosterone. This suggests that higher active testosterone was protective against mortality in this study.