BATON ROUGE — Researchers at LSU's Pennington Biomedical Research Center have found that roughly a quarter of active-duty male U.S. Army personnel register a testosterone measurement below the standard clinical threshold. 

About 25% of active-duty male U.S. Army personnel have a morning testosterone measurement below the standard clinical threshold of 300 ng/dL, according to a study published this week in JAMA by researchers at LSU's Pennington Biomedical Research Center and Purdue University.

The study analyzed data from 479 male participants across five U.S. Army installations between August 2024 and January 2026. Researchers estimated that 25.7% of active-duty male soldiers (roughly 100,690 men) showed low testosterone levels on a single morning test. 

Low measurements were more frequent in soldiers aged 30 and older compared to those under 30, as well as in men with higher body mass indexes.

The findings arrive alongside a Department of War memorandum directing annual testosterone screenings for service members aged 30 and older. However, researchers stressed that a single low screening result does not equal a diagnosis of hypogonadism, as testosterone fluctuates due to stress, obesity, and time of day. Clinical guidelines require repeat testing and symptomatic evaluation before confirming a diagnosis or initiating treatment.