A quarter of troops measured below testosterone thresholds, a study of Army personnel found, with similar results compared to the general U.S. population.
According to the research, published Thursday in JAMA, 20% of male soldiers younger than 30 years had testosterone levels less than the threshold established by the American Urological Association of 300 nanograms per deciliter, or ng/dL. Roughly a third of service members — 32.8% — aged 30 and older fell below the threshold.
According to the analysis, one-time testosterone testing of troops determined that 100,691 active-duty soldiers had morning testosterone levels of less than 300 ng/dL.
The results are an example of what the Department of Defense may encounter under a new program that requires all male service members 30 years and older to be screened for low testosterone, said the researchers from the Pennington Biomedical Research Center in Baton Rouge, Louisiana, and the U.S. Army Research Institute of Environmental Medicine in Natick, Massachusetts.
The results, the researchers said, “suggest that routine testosterone screening will result in confirmatory testing and clinical evaluation for many male service members.
In a video posted to social media, Hegseth said maintaining proper testosterone levels was a way to ensure that troops stay on the “leading edge of lethality.”
“This initiative is not about artificial enhancement. It’s about restoring and optimizing your natural capabilities, protecting your longevity and ensuring you have the biological foundation required to sustain and fight,” Hegseth said.
Environmental exposures, including lead exposure, combat, physical injuries, sleep deprivation and mental health conditions can contribute to low testosterone in service members.
Treatment for severe cases — medically known as hypogonadism — can have serious side effects, such as mood swings, irritability and aggression, blood clots and low sperm count that can cause infertility.
Under the new Defense Health Agency clinical practice guidelines, service members will be screened in the morning on two separate days and assessed for further evaluation if they fall below the 300 ng/dL standard. They may choose to undergo treatment, which involves once- or twice-weekly injections depending on the medication, or a daily oral medication or gel. Treatment will not be mandatory.
The interest in testosterone replacement therapy in the DoD follows a growing $4.5 billion industry centered around testosterone, with the hormone touted as a supplement that contributes to increased physical performance, sex drive, concentration and youthful energy.
Studies in 2018 by the NIH on 800 older men demonstrated that testosterone therapy improved erectile dysfunction, libido and mood, but had little or no improvement on measures such as fatigue, memory or overall well-being.
The research, published Thursday, was based on an analysis of data from the Military Health and Nutrition Examination study, a survey conducted at five Army bases from August 2024 through January 2026.
The authors noted that the low testosterone levels in service members do not indicate that they all had hypogonadism.
A study conducted last year of active-duty men found that .43%, or 12,112 of more than 2.8 million service members, were diagnosed with hypogonadism, and those with the highest rates were the most senior, largely general officers and warrant officers.
The authors of the JAMA research letter cautioned that testing could result in excess medical visits, costs and treatment.
“Positive screening result requires clinical interpretation and typically prompts repeat testing, further evaluation, counseling regarding modifiable factors, and consideration of treatment if indicated. Because testosterone replacement therapy is long term and has potential adverse effects, distinguishing an isolated low screening value from clinically significant hypogonadism is essential,” the researchers wrote.
Patricia Kime is a senior writer covering military and veterans health care, medicine and personnel issues.
