The Pentagon's testosterone plan targets readiness. It misses who actually determines it.

Defense Secretary Pete Hegseth announced in July 2026 that all “warfighters” age 30 and older would receive annual testosterone screening as part of routine health assessments, with optional treatment for those found to have low levels. The program is part of a broader agenda that includes banning beards and long hair and reshaping military health and appearance standards. “Every single day you are pushed to your absolute physical and mental limits to master the profession of arms,” Hegseth said in a video captioned “The High-T Department of War.” “By addressing these health markers early on, we are keeping you on the leading edge of lethality.”

Sebastian Junger — the author who embedded from 2007 to 2008 with an airborne infantry platoon in Afghanistan’s Korengal Valley and co-directed the Academy Award-nominated documentary Restrepo — argues in a Wall Street Journal essay published Thursday that the program does not address the primary factors that determine combat performance. His account, based on firsthand observation of sustained ground combat, describes a force in which the physical demands of the environment already function as the test, and in which the population the screening targets is not the population that determines readiness.

Two independent uncertainties determine where this policy lands: whether the Pentagon builds clinical guardrails into the program before it scales, and whether it limits screening to the combat-arms personnel who actually need it or extends it across a force where most roles depend on skills testosterone does not improve.

The demographic the program assumes is not the demographic it serves

Hegseth’s framing begins from combat — “warfighters,” “the profession of arms,” “lethality.” Junger’s observation begins from the unit he actually lived in.

In the Korengal Valley, Junger wrote, young men carried loads exceeding 100 pounds of gear, ammunition, and weapons at 7,000 feet of elevation in terrain where Taliban fighters moved significantly faster than the American troops. The unit came under fire almost daily. The men were so weighed down on steep hills that they could practically only walk to cover. “There were no women in the unit I was with, and virtually no men over age 30,” Junger wrote.

The physical demands of sustained ground combat effectively serve as a continuous performance test. Men who cannot meet the demands are either removed from combat units or reassigned to rear-echelon positions, Junger wrote. The military’s existing fitness requirements already establish the physical baseline that testosterone levels influence — screening for testosterone deficiency in a population that is already self-selecting for physical performance introduces an additional measure without a clear additional diagnostic value.

But only a small fraction of U.S. service members perform that kind of work. The vast majority serve in non-combat and non-infantry roles, and for those positions testosterone is predominantly a quality-of-life issue rather than a combat-readiness constraint. Even granting that low testosterone in support personnel degrades mood, energy, and cognitive function in ways that touch readiness indirectly, the existing fitness and medical screening systems already monitor the health determinants that matter for those roles — a blanket testosterone screen addresses a biomarker that, for most of the force, sits behind multiple layers of other indicators already under medical oversight. The “lethality” framing is a category error. A screening program that frames the entire force through the lens of combat performance targets the wrong population in the first instance.

What the program does not screen for

Testosterone has been associated in studies with physical strength, elevated red blood cell counts, higher cardiovascular capacity, and aggression. Men can have as much as 20 times more testosterone than women, and their levels typically begin declining around age 30. Obesity, chronic stress, lack of sleep, alcohol abuse, and close-contact infant care can also reduce levels. Supplementation has clinical effects — and clinical risks.

Hegseth’s announcement made no mention of mental health evaluations that might accompany testosterone treatment recommendations. That omission matters because a 2016 study in Biological Psychiatry found that dominant and impulsive men given supplemental testosterone were at risk of acting aggressively within 60 minutes of taking it. Men with those traits who also carry firearms could “put themselves and others at enormous risk,” Junger wrote.

The risk profile the study identifies is not theoretical for a military population: service members routinely carry weapons, operate in high-stress environments, and work within chain-of-command structures where dominance and impulsivity are present in measurable portions of the force. Even if military clinicians started with conservative dosing and post-prescription behavioral monitoring, the absence of a structured pre-screen means no mechanism exists to catch the dominant and impulsive subset before the prescription is written. The risk is structural, not merely pharmacological. It lives in the gap between identifying a deficiency and identifying the personality profile that interacts dangerously with the treatment.

The gap is not whether testosterone affects physical performance — it does, and Junger does not argue otherwise. The gap is that the screening protocol, as announced, does not include a behavioral risk assessment at the treatment stage. In an armed population, that omission is load-bearing.

Which future unfolds depends on what the Pentagon does next

The program faces eight distinct futures, determined by two independent uncertainties the Pentagon has not yet resolved: whether it builds clinical guardrails into the program before it scales, and whether it limits screening to the combat-arms personnel who actually need it. These uncertainties are independent because a program can be designed well and implemented poorly, or designed poorly and embraced enthusiastically by commands that treat it as a leadership signal.

Set A: Medical rigor and institutional adoption

The first four scenarios turn on clinical design and bureaucratic execution.

High rigor, high adoption — Clinical Lethality. DoD establishes clinical practice guidelines that include mental health screening before testosterone supplementation, ongoing monitoring for behavioral side effects, and role-specific thresholds for combat arms versus support. Outcome data is collected systematically and published in military medical journals. The Biological Psychiatry findings on aggression risk are incorporated into screening protocols. This path requires acquiring endocrinology and behavioral health capacity at a scale the military health system currently lacks. The program survives on clinical evidence, not political messaging.

High rigor, low adoption — Paper Protocol. Sound clinical guidelines are drafted, but implementation stalls. Military treatment facilities lack endocrinology specialists. Unit commanders treat screening as an administrative checkbox. Junger’s observation that the combat force is small and self-selecting means most units have little operational incentive to take the program seriously. The military’s existing self-selection mechanisms continue operating unchanged; the policy creates paperwork without measurable readiness effect.

Low rigor, high adoption — Compliance Theater. The program rolls out rapidly across the force, driven by command emphasis and political signaling. The “High-T Department of War” branding sets the tone as a cultural statement about military masculinity. Without clinical guardrails, the Biological Psychiatry aggression findings become operationally relevant. Service members are prescribed supplemental testosterone without behavioral monitoring. Adverse behavioral incidents become more probable. This is the scenario where the gap between political ambition and medical infrastructure produces the highest near-term risk.

Low rigor, low adoption — Initiative Drift. The screening is announced with fanfare and fades. Simultaneous pushes on beards, hair standards, and other appearance regulations fragment institutional attention. The testosterone program receives no dedicated appropriations. No clinical guidelines are finalized. The military’s existing self-selection mechanisms continue operating unchanged. No harm done, but no benefit either.

Set B: Scope and cultural reception

The second four scenarios turn on whom the program targets and how the force responds.

Narrow scope, embrace — Elite Enhancement. Only combat arms personnel receive screening and optional treatment; framed as force multiplier for high-intensity units. Special operations leadership endorses it, citing improved recovery times and endurance. Mental health screening is added after pilot studies show the aggression risk is real but manageable. This scenario aligns with Junger’s own analytical distinction between combat and non-combat roles, and it is the narrowest path to a substantively useful program.

Narrow scope, resistance — Stalled Initiative. Implemented for combat arms but faces internal pushback from traditionalists who argue performance standards already filter inadequate personnel. Bureaucratic inertia limits funding; fewer than 10 percent of eligible personnel get screened. The program survives but is effectively symbolic. If the infantry does not want it, the policy has no constituency.

Broad scope, embrace — Pharmacological Force. Screening extended to all service members age 30-plus, with treatment offered as standard health intervention. Military health system integrates it alongside dental, vision, and nutritional counseling. Testosterone becomes routine part of a “warrior health” package. Mental health protocols developed but vary in quality across branches. The 2016 aggression risk is acknowledged but downplayed. Junger’s “quality-of-life issue” framing becomes the actual policy outcome, though the rhetoric remains about lethality.

Broad scope, resistance — Culture War Front. Force-wide program triggers backlash from traditionalist military circles and from progressive advocacy groups who see it as male-privileging policy. Becomes a political battleground. Recruitment ads featuring testosterone therapy provoke backlash. Program suspended in some branches due to lawsuits. The program’s operational substance is subsumed by political polarization.

What to watch

Concrete signals will indicate which scenario is unfolding. The scenario-discriminator thresholds described below are analyst-supplied benchmarks, not existing data points, and they function to distinguish which future is arriving.

If the Defense Health Agency director testifies before the Senate Armed Services Committee within 90 days of program launch with specific references to clinical protocol design and mental health safeguards, the program is moving toward Clinical Lethality. If GAO publishes a report within 24 months documenting that fewer than 40 percent of eligible service members received screening consistent with clinical guidelines, the program is heading toward administrative drift. If TRICARE pharmacy data — a scenario planning heuristic, not an established metric — shows a year-over-year increase exceeding 15 percent in testosterone prescriptions among active-duty males within 12 months of launch with no corresponding adverse-event reporting system in place, the program has deployed at speed without the infrastructure to manage what comes next. If a major veterans’ organization such as the American Legion or VFW issues a public statement opposing the program, the scenario is Culture War Front.

Other signals: GAO or Inspector General report identifying resource gaps with no published outcome data after 18 months (Paper Protocol); FY2028 defense appropriations bill containing no line item for testosterone screening with no reference in the Pentagon’s annual force health report (Initiative Drift); 25 percent or more of SOF operators voluntarily opting into screening within the first year (Elite Enhancement); fewer than 5 percent of eligible soldiers in the 1st Infantry Division completing screening by end of 2027 (Stalled Initiative); 80 percent or more screening compliance across all branches with TRICARE adding testosterone therapy to its formulary without restriction (Pharmacological Force); whistleblower complaints about pressure to undergo treatment, congressional investigations, and a drop in female enlistment (Culture War Front).

Wild cards

Two events sit outside all four quadrants in both axis sets.

A supplementation incident. A high-profile incident — a training accident or operational event — involving a service member prescribed supplemental testosterone. If aggression-related misconduct, it triggers immediate congressional scrutiny, a moratorium, and mandatory mental health screening requirements, jumping the matrix toward Clinical Lethality by force. If the incident involves exceptional combat performance, it becomes a political proof-of-concept that accelerates adoption regardless of what the medical evidence supports. If the perpetrator had a known dominance or impulsivity history — the Carré et al. risk profile — the event is more probable under low-rigor scenarios. Either outcome restructures the policy landscape outside the four quadrants: a single event can shift the policy from any scenario to any other, or to a state not captured by the axes.

A doctrinal reframing. A sudden shift in the strategic environment — direct military confrontation with a peer adversary such as China over Taiwan or Russia in the Baltic — redefines “combat readiness” around technical proficiency, electronic warfare capability, cyber operations, and long-range precision fires rather than infantry endurance. The infantry-centric physical-performance framing that underpins Hegseth’s testosterone initiative becomes a secondary concern. Congressional and Pentagon attention redirects to capability gaps with near-peer adversaries. The testosterone program, never formally cancelled, is deprioritized into irrelevance — not because it failed, but because the definition of the problem it was designed to solve changed fundamentally. It sits outside the matrix because it changes the problem definition rather than varying the policy response. Indicator: increased frequency of military exercises with near-peer adversaries; shift in defense budget language from “readiness” to “modernization” and “deterrence”; establishment of new doctrinal publications that de-emphasize physical fitness standards relative to technical qualifications in combat-arms branches.

What the evidence says about which path the Pentagon is on

The program’s conception reflects a narrow experience base applied to the entire force. Hegseth guarded detainees at Guantánamo Bay, served as a civil affairs officer in Iraq, taught counterinsurgency classes in Afghanistan, and was awarded two Bronze Stars for “meritorious service” — distinct from “valorous service” for combat — and received a combat infantry badge for coming under fire in Iraq. As a member of the Washington, D.C., National Guard, he was blocked from serving at President Biden’s inauguration after a fellow Guard member flagged him as a possible “insider threat” because of a tattoo “closely associated with violent white nationalism,” Junger wrote. That a defense secretary whose combat exposure was confined to a narrow slice of combat-adjacent roles now prescribes a “lethality” program for the entire force illustrates the conceptual slippage at the heart of the policy: a program born of a narrow experience base is being applied as a universal readiness measure. The mismatch mirrors the demographic problem the analysis identifies.

Robust strategies

Two strategies hold regardless of which scenario unfolds.

First, differentiated protocols by military occupational specialty — separate screening and treatment guidelines for combat arms versus support roles — would address the structural gap Junger described between the Korengal Valley platoon and the broader force.

Second, requiring independent mental health evaluations before any testosterone therapy is offered would mitigate the Carré et al. aggression risk and protect both readiness and the program’s legitimacy. Whether either safeguard is added depends on decisions the Pentagon has not yet made.

What remains unresolved

Whether the clinical infrastructure — endocrinology specialists, mental health screening protocols, behavioral monitoring systems — materializes before treatment recommendations are issued to an armed force of 1.3 million people is the central question the scenario analysis surfaces. It is answerable within the next 90 days. Whether the program is scoped to the population where testosterone levels determine combat performance or extended force-wide determines whether the policy addresses its stated rationale or becomes a general health intervention framed in combat language. What happens to the policy if an adverse behavioral incident linked to supplemental testosterone becomes public will test whether the initiative can survive scrutiny without the safeguards Junger identifies as absent. Whether the military force of the next decade — shaped increasingly by drone warfare, cyber operations, and long-range precision fires rather than infantry endurance in terrain like the Korengal — even defines “combat readiness” in the physical-performance terms this program assumes is a question the policy’s design does not appear to have considered.

Analytical techniques used in this piece

This analysis applies the methods below. Each links to a short, plain-English explainer you can read and reuse.

Quick Orientation

A fast lay-of-the-land read of an unfamiliar domain.

Red-Team Assessment

Models a capable adversary probing a plan for the seams they would exploit.

Scenario Planning

Builds a small set of distinct, plausible futures to plan against.