The US military will introduce annual testosterone screening for personnel over the age of 30, with the tests offered on a voluntary basis.
Defence officials say the initiative is designed to help service members operate at their absolute best through improved long-term health and resilience.
Any military member found to have low testosterone will be offered voluntary hormone replacement therapy. Current regulations prohibit testosterone use for non-medical reasons, and officials stress the programme is not intended as artificial enhancement.
A Pentagon spokesman said the protocol will establish a comprehensive health baseline and provide targeted therapy to sustain a capable and dominant fighting force.
The Defence Secretary announced the screening alongside a video promoting the effort, describing it as part of delivering the best medical care to the nation's warriors.
Since taking office, the Defence Secretary has renamed the agency the Department of War and shifted focus toward a more overtly masculine and religious framing of military identity.
The approach has included aggressive responses to press questioning on ongoing operations, including comments praising the conduct of recent conflict and dismissing critics.
At the start of the Iran conflict, reports emerged that some personnel were told the war was "God's plan" to bring about the end of the world. More than 200 complaints were filed across all branches of the armed forces.
One complainant described a commander opening a combat readiness briefing by urging troops to view the looming threat as part of a divine plan, citing biblical passages on Armageddon and the return of Christ.
Officials said the commander made the remarks with a smile, according to a copy of an internal email documenting the incident.
