What to know about testosterone replacement therapy
U.S. Secretary of Defense Pete Hegseth speaks at a press conference at the Pentagon in Washington, DC, on April 8, 2026.
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Testosterone replacement therapy has shifted from the doctor’s office to the center of a massive cultural phenomenon focused on performance, longevity and men’s health.
The treatment came back to the agenda after Defense Secretary Pete Hegseth’s statement last week. US army will begin tests Raising service members’ testosterone levels and offering replacement therapy to those who qualify, the goal is said to be to help troops function at their “absolute best.” The effort also builds on a larger push by the Trump administration to promote and expand public access to testosterone replacement therapies made by pharmaceutical companies such as AbbVie, Pfizer and Marius Pharmaceuticals.
The announcement puts new focus on a treatment that has become increasingly popular in recent years, promoted by men’s health clinics, telehealth companies and online influencers promoting testosterone, or “T-maxxing,” as a way to address fatigue, aging and performance decline. Secretary of Health and Human Services Robert F. Kennedy Jr. He also suggested that testosterone therapy is part of his anti-aging regimen.
Prescriptions have increased from 7.3 million in 2019 to more than 11 million in 2024, according to health research company IQVIA. But there has long been a debate about the safety of taking synthetic forms of testosterone, the hormone that affects sex drive, mood and other health factors.
Although some studies show benefits for qualifying patients, including improvements in bone density and muscle mass, questions remain about the treatment’s long-term risks and its use in men without a clear medical need.
The concern is significant: Up to a third of men taking testosterone never officially diagnosed People with testosterone deficiency may not benefit from treatment, according to the American Urological Association.
Doctors also emphasize that testosterone therapy is not a universal solution for low energy or normal aging. It’s usually aimed at men with clinically confirmed testosterone deficiency, and experts say it takes more than a single blood test to determine who qualifies, which appears to be the military’s plan. Excess testosterone can also carry risks, including reduced sperm production.
Endocrinologist Dr. from Johns Hopkins School of Medicine. “I’m not saying testosterone is bad. It’s good for people who need it,” said Adrian Sandra Dobs. “But we have to be very careful about this to not change it too much.”
As testosterone therapy enters a new national debate, here’s what doctors say we know and don’t know about the treatment’s benefits, risks, and who should consider the treatment.
Who is the therapy aimed at?
Testosterone replacement therapy, commonly administered through injections, gels, implantable pellets, and oral medications, is aimed at a narrower population than social media might suggest.
Doctors say this is usually reserved for men who have been clinically diagnosed with hypogonadism (a condition in which the body does not produce enough testosterone).
This usually means persistently low testosterone levels, along with symptoms such as decreased sexual desire, fatigue, erectile dysfunction, depressed mood, low bone density or loss of muscle mass and strength.
Low testosterone can occur for a variety of reasons, Dobs said. Although testosterone levels naturally decrease with age, this alone does not qualify as a deficiency. Certain conditions can also suppress testosterone production, including sleep disorders such as sleep apnea, damage to the testicles, pituitary disorders, some cancer treatments, and chronic diseases.
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In some men, doctors may diagnose a condition known as functional hypogonadism, in which testosterone levels drop due to potentially reversible factors such as obesity or chronic disease, even if the reproductive organs are structurally intact.
“Obesity, stress, fatigue, and inadequate sleep are very common, and these conditions can reduce testosterone,” said Marcus Goncalves, M.D., director of the Holman Division of Endocrinology, Diabetes, and Metabolism at NYU Langone Health. “The right solution is to improve these aspects and allow testosterone to rise again naturally, but this is easier said than done.”
But diagnosing this condition often requires more than a single blood test, Goncalves added.
Because testosterone levels fluctuate throughout the day, medical guidelines generally recommend confirming low levels with two separate blood draws in the morning and evaluating patients for potential underlying causes before considering treatment.
A low testosterone result does not always mean someone needs treatment. Professor of internal medicine at the University of Michigan, Dr. During periods of severe stress, illness, weight loss or intense physical exertion, testosterone levels may drop temporarily and return to normal once these factors are eliminated, said Richard Auchus.
“It’s not so easy to tell whether a person’s testosterone level is adequate and whether this is a functional and reversible condition or whether this is a permanent problem that is irreversible,” Auchus said.
What are the potential benefits and risks?
The benefits of testosterone replacement therapy can be real for the right patients.
“I would say we try to limit treatments to people that we know will benefit,” Auchus said.
In men with clinically confirmed testosterone deficiency, treatment may increase sex drive, improve erectile dysfunction, help restore muscle mass and bone density, and improve energy levels and mood. It may also reduce the risk of osteoporosis and fractures in men with low hormone levels by improving bone mineral density.
But experts say it’s less clear whether boosting testosterone in people who already have normal or only mildly low levels provides meaningful benefits in terms of energy, cognitive ability, athletic performance or overall health. They added that evidence supporting the use of testosterone as a broad anti-aging or performance-enhancing treatment remains limited.
“It doesn’t make you smarter. It doesn’t make you a better pilot,” Dobs said.
Even for suitable patients, testosterone therapy carries risks and requires constant monitoring, doctors say.
NYU Langone’s Goncalves said one concern is that the treatment could increase red blood cell counts, potentially thickening the blood and increasing the risk of complications such as blood clots.
While earlier studies raised concerns that testosterone therapy may increase cardiovascular risk, more recent evidence has been reassuring. A. Big trial in 2023 The largest and most comprehensive study to date found no higher rates of heart attack, stroke or cardiovascular death in men receiving testosterone therapy compared to those given a placebo.
Researchers observed higher rates of certain conditions such as atrial fibrillation, acute kidney injury, and pulmonary embolism, underscoring the need for careful patient selection and monitoring.
He added that the treatment may also suppress the body’s natural hormone production, reducing sperm production and potentially affecting fertility. Doctors generally do not recommend testosterone therapy in men who want to have children.
Other potential side effects include acne, breast tenderness or enlargement, fluid retention, and worsening symptoms of untreated sleep apnea.
How might this apply to the military?
The Army’s plan to test soldiers’ testosterone levels raises an important question: How should doctors interpret hormone levels in people exposed to extreme physical and psychological stress?
Intense military training, sleep deprivation and prolonged physical exertion can temporarily suppress testosterone production, Goncalves said. Inside a study Testosterone levels of U.S. Marines undergoing Survival, Evasion, Resistance and Escape, or SERE, training dropped by about half during exercise and recovered afterward.
“There is no evidence that it was restored [testosterone] “The levels during this period are improving performance,” he said, but added that the issue was worth studying.
Some experts said it also underscores a challenge for any large-scale testing program. A low testosterone value may reflect a temporary response to challenging conditions, rather than a permanent deficiency requiring treatment.
Auchus also warned that testosterone therapy could create long-term problems for healthy soldiers. Because the treatment suppresses the body’s natural testosterone production, men who continue treatment for long periods of time may become dependent on it to maintain normal hormone levels, he said.
This raises questions about what might happen if a soldier taking testosterone suddenly cannot access the treatment during a deployment or other military operation, Auchus said.
More generally, experts say testosterone replacement therapy should not be viewed as a shortcut to improving military performance.
“Testosterone is not going to make men more macho or better fighters,” Dobs said. “To win the war, you need intelligence.”
