United States Defense Secretary Pete Hegseth has ordered mandatory testosterone testing for all active-duty and reserve military personnel aged 30 and over, with those younger than 30 able to opt in voluntarily. Announcing the initiative in a video titled "The High T Department of War" posted on July 15, Hegseth framed the policy as essential to combat readiness, stating that while the military invests heavily in weapons systems and equipment, "our most critical tactical advantage will always be the individual warfighter" — and that maintaining that advantage is a "sacred obligation." Personnel found to have low levels will be offered testosterone replacement therapy (TRT) on a voluntary basis.

The announcement, which was accompanied by a brief Pentagon press release and internal memo, leaves many implementation questions unanswered. It is unclear whether low testosterone readings could affect promotions or lead to discharge, whether personnel could request a retest after an initial low result, and whether female service members — who naturally have lower testosterone levels but for whom the hormone also plays a physiological role — will be included in the programme. The Pentagon has not responded to media questions about the scientific research underpinning the policy, nor about whether female personnel might be screened for oestrogen.

Medical experts have raised significant concerns about the policy's clinical basis. Standard guidelines from the American Urological Association require two separate measurements taken on different mornings — when testosterone peaks — before a diagnosis of low testosterone can be made, and the person must also present relevant symptoms such as reduced libido or erectile dysfunction. A single reading, which is what mass screening typically produces, can fluctuate considerably. Active-duty personnel are generally healthier than the broader population, meaning widespread screening risks producing false positives — telling healthy soldiers they are "deficient" when they are not. Furthermore, the "voluntary" nature of treatment may carry implicit pressure in a military hierarchy, where personnel offered therapy after a low result may feel compelled to accept it regardless of symptoms.

Testosterone replacement therapy itself carries established risks for men without confirmed symptomatic hypogonadism, including elevated red blood cell volume — which raises the risk of heart attack, stroke and blood clots — as well as reduced sperm production, infertility, acne, and physiological dependence that makes stopping treatment difficult. While TRT is a proven treatment for clinically diagnosed hypogonadism caused by disorders of the testes, pituitary gland or hypothalamus, its use among otherwise healthy men seeking a physical boost lacks a clear evidence base for benefit.

The policy reflects a broader cultural moment in the United States, where testosterone has become commercially and politically charged. Annual US sales of testosterone gels and patches surpassed two billion dollars as early as 2013, and the number of Americans using such products may now exceed ten million. Health Secretary Robert F. Kennedy Jr., who has publicly endorsed TRT as part of his personal anti-ageing regimen, has made unsubstantiated claims that testosterone levels in American teenagers are lower than those of men in their late sixties. The Food and Drug Administration under Kennedy has also recently loosened prescribing restrictions on testosterone. Critics argue that by embedding testosterone levels as a measure of "manhood" and "lethality" in official military policy, the Hegseth directive gives institutional legitimacy to what had previously been a fringe, social-media-driven movement — one that treats hormonal status as a proxy for masculine worth rather than a nuanced medical indicator.