Low T? High T? What a new medical study reveals about US soldiers' testosterone levels

SALT LAKE CITY — Defense Secretary Pete Hegseth announced a few months ago that male U.S. military service personnel who have hit their 30s will now be tested annually for testosterone deficiency.

The new mandatory screening program for "warfighters ages 30 and older," Hegseth said, will ensure they "have the right testosterone levels to operate at their absolute best — because it's well-established science that as we age, testosterone levels naturally drop."

Servicemen diagnosed with low testosterone can volunteer to receive treatment, with the Defense Department picking up most of the tab.

Now a study released Thursday by the Journal of the American Medical Association suggests a sizable number of troops in their 30s could be potential candidates for testosterone replacement therapy.

In a multisite survey conducted at five U.S. Army installations from August 2024 through January 2026, approximately one-quarter of the 479 tested soldiers had a single morning testosterone concentration of less than 300 nanograms per deciliter, or ng/dL. Those results are similar to estimates in the general U.S. population.

A testosterone level less than 300 ng/dL is considered a reasonable cutoff for low testosterone, according to the American Urological Association.

As expected, the low testosterone rate in the survey was higher with troops aged 30 and older. Almost a third of that demographic had testosterone concentrations below 300.

"Although lower testosterone concentrations were more common in older men and those with higher BMI, low screening values were also observed in younger service members," added the JAMA report.

Almost 20% of male soldiers younger than 30 also fell below the ideal testosterone threshold.

This week's JAMA report could foreshadow what the Pentagon may be facing following Hegseth's recent order that all male troops ages 30 and above be tested for testosterone deficiency.

Researchers from the Pennington Biomedical Research Center and the U.S. Army Research Institute of Environmental Medicine told Military Times that the results "suggest that routine testosterone screening will result in confirmatory testing and clinical evaluation for many male service members."

Inconclusive research

The JAMA report cautioned that its screening estimates should not be interpreted as conclusive evidence of hypogonadism — or low testosterone.

"A low morning testosterone concentration," the report noted, "must be confirmed by repeat testing before diagnosis of hypogonadism."

Many men with a single low screening measurement do not have "clinical hypogonadism." Instead, an initial positive low testosterone result typically prompts repeat testing and further evaluation and treatment considerations.

"Because testosterone replacement therapy is long-term and has potential adverse effects, distinguishing an isolated low screening value from clinically significant hypogonadism is essential," according to the JAMA report.

The Pentagon's testosterone deficiency confirmation procedure calls for two morning fasting tests when low testosterone is suspected.

Trump administration's support for testosterone therapy

The Trump administration's advocacy for aggressive testosterone management stretches beyond the Pentagon.

The Department of Health and Human Services, led by Secretary Robert F. Kennedy Jr., proposed earlier this year to loosen restrictions on the therapy, according to NBC News.

The move came after a Food and Drug Administration panel in December called for regulatory changes to make testosterone therapy more accessible.

Kennedy has previously said that he was taking testosterone replacements, which he said were "appropriate for my age."

Since 2015, NBC News noted, testosterone replacement therapies have carried warning labels and have only been available to men who have both low testosterone and an associated medical condition.

Although some past research has linked the therapy to strokes, heart attacks and death, a 2023 study known as the TRAVERSE trial found that testosterone replacement therapy did not increase the risk of heart attacks and strokes.

Health officials in the Trump administration have also reportedly touted the potential benefits of hormone replacement therapy for women. The FDA last year removed black box warnings on the therapies for menopause.

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