Military personnel often face extreme physical and mental challenges, operating in high-stress environments where quick decisions and precise actions can mean the difference between life and death. To prepare for these situations, soldiers rely on rigorous training programs designed to build physical and mental resilience. However, even the most comprehensive strategies struggle to address the intense energy demands of deployment. Limited food intake and prolonged exertion often lead to energy deficits that can weaken the body and mind.

These energy deficits can trigger a chain reaction of negative effects. One major issue is a drop in testosterone levels—a condition called hypogonadism. Testosterone is crucial for maintaining muscle and bone strength, cognitive function, and overall health. When levels plummet, soldiers may experience muscle loss, weakened bones, reduced physical performance, slower decision-making, and a compromised immune system. This not only impacts their own safety but also the safety of their team.

Young men typically have testosterone levels ranging from 10.4 to 34.7 nmol/L (300–1000 ng/dL). Yet, studies show that military training and deployment can cause testosterone levels to drop by as much as 65%. To counteract this, researchers are exploring testosterone replacement therapy (TRT) as a potential solution. TRT involves administering synthetic testosterone, like testosterone enanthate, through weekly injections. This approach has shown promise in improving muscle mass, bone strength, mood, cognition, and overall resilience in men with low testosterone levels in civilian populations.

A groundbreaking study led by the U.S. Army Research Institute of Environmental Medicine recently tested TRT’s effectiveness in a military setting. The study followed soldiers over a 28-day period, during which they experienced controlled energy deficits and received weekly testosterone injections. The results showed reduced weight loss and increased lean muscle mass, leading to improvements in body composition and health. However, the study’s short duration limited its ability to capture long-term effects, such as gains in muscle strength.

Longer-term studies are needed to fully understand TRT’s potential benefits and risks for soldiers. Research has already shown that testosterone supports long-lasting muscle and bone health, which could help prevent injuries like stress fractures and aid recovery after missions or injuries. It might also delay conditions like osteoporosis and muscle loss later in life.

One lingering concern is whether TRT increases the risk of aggressive prostate cancer. However, current evidence suggests that higher testosterone levels in young men are not linked to increased cancer risk or severity, making TRT a potentially safe option for military personnel.

Future research should focus on longer studies to confirm TRT’s benefits and address potential risks. Additionally, as more women join combat roles, it will be important to study how severe stress affects female hormonal health and whether similar treatments could be developed.

Testosterone replacement therapy offers a promising way to enhance soldier performance and reduce injury risks, but further research is essential to optimize its use in military settings.