Defense Secretary Pete Hegseth has launched a nationwide debate about testosterone and men’s health with a new Pentagon directive aimed at screening service members for hormone deficiency.

The policy, announced on July 15, directs the Department of Defense to begin mandatory testosterone-deficiency screening for active-duty and reserve personnel age 30 and older as part of regular health assessments, with optional testing available for younger troops.

According to the Associated Press, testosterone replacement therapy will be voluntary for men diagnosed with confirmed deficiency.

A Pentagon statement said the initiative seeks to “optimize performance, combat ‘Operator Syndrome’ and maximize mission readiness,” emphasizing readiness and overall wellbeing among male personnel.

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Dr. Marc Siegel, Fox News senior medical analyst, told Fox News Digital that he supports the approach. “I already screen for it in men over 50, and it makes sense to check for it in men who rely on tip-top physical performance,” he said.

The effort comes amid differing opinions from medical organizations. The Endocrine Society does not recommend broad testosterone screening for men without symptoms, citing insufficient evidence for routine population-level testing.

The society lists the normal range for healthy, non-obese men ages 19 to 39 as 264 to 916 nanograms per deciliter, though laboratories may vary in their reference numbers.

The American Urological Association considers levels below 300 nanograms per deciliter, accompanied by related symptoms, as deficient. The Endocrine Society estimates that about 2% of men overall have hypogonadism, a condition that becomes more common with age and certain health conditions like obesity or diabetes.

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“Low testosterone can cause chronic fatigue, weight gain, bone and muscle loss, cognitive problems and increased body fat,” Siegel said.

Over time, men with untreated deficiency may also experience hair loss, lower bone density and anemia, according to the Endocrine Society. Sexual issues such as reduced libido or erectile dysfunction tend to be more specific indicators.

Because testosterone levels fluctuate by time of day and other factors, diagnosis usually requires low results on two early-morning, preferably fasting, blood tests along with characteristic symptoms.

If confirmed, additional testing may be performed to determine cause. Luteinizing hormone can help identify where the problem originates, while follicle-stimulating hormone and prolactin levels may be checked when fertility or pituitary function is questioned.

Doctors also sometimes measure free testosterone — the portion available for use — if total levels do not align with symptoms.

Before starting testosterone replacement therapy, physicians typically evaluate for reversible factors such as obesity, alcohol use, medication side effects and sleep apnea. For men whose low levels stem from obesity, lifestyle changes and weight loss are viewed as first-line treatments.

The Endocrine Society notes that TRT can be administered as gels, patches, injections, nasal formulations or implanted pellets, depending on clinical need.

In June 2026, the Department of Health and Human Services announced it had asked the Food and Drug Administration to revise labeling on testosterone therapies after reviewing new clinical data. The proposed updates would remove older language questioning TRT’s safety in men with age-related hypogonadism and reflect newer prostate cancer research.

“We are putting science back at the center of men’s healthcare,” HHS Secretary Robert F. Kennedy, Jr. said in a statement. He added that updated labels would “support informed medical decisions and improve care for millions of American men.”

The changes only concern drug labeling and do not alter existing treatment guidelines. Certain men remain ineligible for TRT, including those with active prostate or breast cancer, high hematocrit, untreated severe sleep apnea, recent heart attack or stroke, or conditions that cause abnormal blood clotting.

Men seeking fertility are also advised to avoid TRT, since it can suppress sperm production. Those undergoing therapy are typically monitored through hormone checks, blood counts, prostate screening and symptom review.

In 2023, the Cleveland Clinic–led TRAVERSE trial published in The New England Journal of Medicine found that TRT did not raise overall rates of heart attack, stroke or cardiovascular death compared to placebo in men with low testosterone and preexisting cardiovascular disease or risk.

However, the study did note increased risks of pulmonary embolism, kidney injury and atrial fibrillation, reinforcing the importance of regular monitoring.

A later substudy found a slightly higher fracture rate among men on TRT, underscoring that benefits must be weighed against individual risks.

“The results provide long-awaited reassurance about the cardiovascular safety of testosterone therapy when used as indicated,” said senior author Dr. Steven Nissen of Cleveland Clinic. He cautioned that the findings should not encourage widespread prescribing beyond appropriate cases.

While testosterone therapy can improve libido, anemia, bone density and lean muscle mass, experts note that it is not guaranteed to enhance energy or cognition in every patient.

As Hegseth’s initiative unfolds across the armed forces, it has reignited broader interest in how testosterone levels influence health, performance and aging for men nationwide.