Testosterone, the next miracle drug? It seemed to be the consensus of a group of experts convened by the United States Food and Drug Administration (FDA) in December. He advocates for major policy changes that would expand access to the hormone to people suffering from a variety of conditions. Committee members called testosterone replacement a “cornerstone of preventative health” and a “multibillion-dollar preventive care opportunity.”
Testosterone is already available in the United States for people whose hormone levels are low due to a known medical problem, such as testicular damage. But there is growing evidence that more men – and women – could benefit from the hormone, administered by injections, patches, subcutaneous implants or gels. (This article uses “men” and “women” to reflect the language used by cited panels and studies, while recognizing that trans, non-binary, and intersex people are also affected by this issue.)
The committee’s recommendations intensify a raging debate over who could benefit from the treatment. Some clinicians say that most men with low testosterone, especially young men without any medical conditions contributing to the problem, do not need additional treatment at all and should be able to increase their testosterone levels by adopting a healthier lifestyle and losing weight. Others argue that men with low testosterone and symptoms such as low libido, fatigue, and irritability could benefit from the therapy.
On supporting science journalism
If you enjoy this article, please consider supporting our award-winning journalism by subscribe. By purchasing a subscription, you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
The most enthusiastic supporters, including many members of the FDA panel at the December meeting, take a third view: All cis men should be tested, and those with low testosterone levels should be treated even if they have no symptoms. “A strong argument could be made that having normal testosterone levels is important for health and disease prevention,” says Abraham Morgentaler, a urologist at Harvard Medical School in Boston, Massachusetts, who participated in the December panel.
Morgentaler and other panelists emphasized at the meeting that testosterone isn’t just a “lifestyle drug” that men take to build muscle and feel good. Yet it’s increasingly marketed this way. Podcasters such as Joe Rogan and his guests sang the hormone’s praises. And dozens of testosterone clinics are popping up around the world, promising fitter bodies and increased energy levels to people who may not even have low testosterone to begin with.
At high doses, testosterone use potentially carries risks ranging from infertility to increased mortality. The drug is currently classified as a controlled substance with abuse potential in the United States and several other countries, in part due to doping scandals in the 1990s and 2000s. This classification is worth reconsidering based on statements made by FDA Commissioner Marty Makary, who also expressed enthusiasm for testosterone during the December panel.
So what is the evidence for the safety and benefits of testosterone replacement?
Security file
Testosterone’s reputation has ebbed and flowed since the hormone was first synthesized in the 1930s. After an initial golden period, during which it was described as “one of the most powerful drugs recently introduced into medicine”, the therapy fell out of favor over fears that it could cause cancer. This idea originated from the work of urologist Charles Huggins who, in 1941, discovered that prostate cancer is dependent on testosterone and that decreasing hormone levels led to fewer tumors. It was a revolutionary discovery for which he received a share of the Nobel Prize in Physiology or Medicine in 1966.
Morgentaler says that when he was training as a urologist in the 1980s, there was a widely held belief, based on Huggins’ findings, that testosterone treatment could promote prostate cancer. Despite the alleged risks, he says he still thought the hormone might help some of his patients who had low testosterone and sexual problems. So he began to treat them while monitoring them closely.
They didn’t get cancer, Morgentaler says, and they benefited greatly from the treatment. Some of his clinical discoveries—along with the revelation that Huggins’ most dire warnings about the cancer-causing hormone were based on the observations of a single person—helped pave the way for renewed interest in testosterone therapy. Morgentaler is widely recognized for his work on the safety of testosterone, although some clinicians disagree with him on the extent to which men might benefit from this hormone. Morgentaler notes that he has consulted with companies that sell testosterone in the past, but says he has no current financial interest.
Other potential risks have emerged over time. Two retrospective studies from 2013 and 2014 found an increased risk of heart attacks in men taking testosterone treatment, leading the FDA to add a warning to testosterone product labels in 2015.
But a randomized clinical trial involving about 5,200 men – called TRAVERSE – found that middle-aged and older men with low testosterone and a high risk of cardiovascular disease who took the hormone did not have a higher incidence of serious cardiovascular events, including heart attack and stroke, than those on placebo. “This study only selected very sick people, the highest-risk population, and nothing serious happened to them,” says co-author Mohit Khera, a urologist at Baylor College of Medicine in Houston, Texas. He also participated in the FDA’s expert panel and says he consults with testosterone companies.
Based on the results of TRAVERSE, the FDA removed cardiovascular warning testosterone products last year.
TRAVERSE’s safety evidence refers to men with confirmed low testosterone levels – below 300 nanograms per deciliter of blood serum – who are treated to return their levels to the normal range of 350 to 750 nanograms. However, higher doses, which push levels well above the natural range, carry dramatically different risks.
In high doses, testosterone can thicken the muscles of the heart, impairing its ability to pump blood, a condition called cardiomyopathy. High testosterone levels can also cause infertility, testicular shrinkage, lower sperm count and erectile dysfunction, says Channa Jayasena, an endocrinologist at Imperial College London. There are also neuropsychiatric effects, including irritability and even psychosis, that could increase the risk of violent crime and domestic violence, says Jayasena, who advises companies that sell testosterone but says he refuses payment to avoid a conflict of interest. “For reasons we don’t fully understand, very high doses of testosterone do something that therapeutic testosterone doesn’t do,” he says.
A Danish study that followed some 500 men using high doses of anabolic steroids — which include medically approved testosterone products and other variations of the hormone — found that their mortality rate was three times higher than that of non-users over a period of about seven years, a risk that Jayasena says is similar to that of cocaine use. Study participants were captured by a doping control program that inspects fitness centers in Denmark and tests people suspected of steroid abuse. The authors acknowledge that steroid use has been associated with risky behaviors, which could partly explain the increased mortality.
This form of misuse is also addictive: around 30% of men taking high doses become dependent. “They are flooding our clinics,” adds Jayasena.
Who can benefit from it?
Clinicians who push for wider use of testosterone often share striking anecdotes about the hormone that transforms people’s lives. Morgentaler says that when he began treating people with low testosterone levels in the late 1980s, they reported things like “My wife still loves me” and “I’ve never had so much patience with my young children.” Regularly, they tell him that they finally feel like themselves again, with improved mood, vigor and libido. They go from feeling exhausted, like their fuel tank is empty, to regaining endurance and thriving at work, Morgentaler says.
These testimonials come from people who follow the therapy; many give up. In the TRAVERSE trial, approximately 61% of participants receiving testosterone stopped treatment. There’s little research on why men stop taking testosterone, but Morgentaler speculates that some don’t like the way it’s administered and others simply don’t feel the benefits (perhaps, he says, because they take the wrong dose or have unrealistic expectations).
Clinical trials only confirm a modest portion of the benefits that testosterone enthusiasts tend to attribute to it.
The clearest effect is on sexual function. A subanalysis of the TRAVERSE trial, which included about 1,100 men with low libido, found that both the treatment and placebo groups increased their sexual activity, but the increase was 25% higher in treated men. Sexual desire also improved with testosterone treatment, but erectile function did not.
A meta-analysis commissioned by the Endocrine Society, an organization based in Washington, DC, concluded that testosterone was associated with a “small but statistically significant” improvement in sexual function, sexual satisfaction and libido in men with low testosterone levels. The study also found a slight improvement in erectile function, unlike the TRAVERSE trial. The review found no statistically significant differences in energy, mood or cognition.
Other studies have shown that testosterone treatment can effectively treat anemia and that it improves bone density. Surprisingly, men receiving testosterone in the TRAVERSE trial had more fractures than those taking placebo. “He “We need to get these inactive men to become more active,” which could be a good thing if it means they exercise more, Jayasena says.
Smaller trials have shown that testosterone is also associated with increased fat-free body mass and muscle strength in both younger and older men.
Potential benefits for women
While testosterone use is increasing in some groups, many people who could benefit from it have mostly been excluded from the debate, including trans men, for whom the hormone is recommended as part of gender affirming careAnd menopausal women.
For women, the only indication for which there is clear evidence of benefit is low sexual desire after menopause that causes distress, according to a systematic review and meta-analysis of 36 randomized controlled trials.
Susan Davis, an endocrinologist at Monash University in Melbourne, Australia, and co-author of the review, says there is huge variation in how women respond to testosterone treatment. Just having a doctor who listens to their concerns, validates them, and cares for them is enough for some women to report feeling better. “I’ve now studied testosterone in thousands of women and I’ve probably done more clinical trials on testosterone than anyone else,” says Davis, who consults with companies that sell testosterone and received a grant from one. “What we’ve seen time and time again in all of our studies is an incredible placebo effect.” Testosterone does better than placebo in terms of sexual function, but the data does not show a significant difference in terms of well-being, cognitive health and body composition.
The recommended doses – which aim to restore testosterone levels to those of premenopausal women – are generally safe, leading to side effects such as acne and body and facial hair.
High doses, however, are associated with side effects that some patients might find more unpleasant, such as hair loss, weight gain, voice change, and clitoral enlargement. “It’s pretty painful,” Davis says.
She has seen people who had already been prescribed high doses and who reported agitation and aggression. Some people say they experienced road rage for the first time. “One woman told me she woke up in the middle of the night with her hands around her husband’s neck. A band from a dream,” Davis says. Stopping treatment can also be difficult. Some women who stop suddenly after taking high doses “may feel very flat and miserable,” she says.
Only four countries have testosterone products approved specifically for women: Australia, New Zealand, South Africa and, as of last year, the United Kingdom.
Elsewhere, women use testosterone formulations designed for men, which could put them at risk, Davis says. This type of off-label use is widespread in the United States. “It seems to me that the FDA would protect women by approving a specific dose formulation for women,” she says. In December, the FDA panel did not discuss the use of testosterone for trans women or men.
Regulatory hurdles
The FDA currently limits approval of testosterone products to treating “classical hypogonadism,” in which low testosterone is caused by genetic conditions or disorders of the brain or testicles. In the UK, Europe and Australia, testosterone is approved for the treatment of men with laboratory-confirmed low testosterone levels accompanied by symptoms. There need not be an identified cause of the impairment. This is also the position of most clinical guidelines from urology and endocrinology associations around the world.
But the more restrictive regulatory scenario in the United States is already starting to change. In April, the FDA announced that it was inviting pharmaceutical companies to submit applications for testosterone therapy for the treatment of low libido in men with low testosterone levels for an unknown cause.
So far, no further changes have been made to the U.S. regulations based on proposals discussed by the panel, such as removing the classification of testosterone as a controlled substance or recommending routine testosterone testing for all men. But other changes could still follow.
One argument for including testosterone testing in routine preventive care, said panelist Helen Bernie, a urologist at Indiana University in Carmel, is that low levels have been linked to a range of health risks. For example, Bu Yeap, an endocrinologist at the University of Western Australia in Perth, and colleagues reported that older men with low testosterone were at higher risk of stroke. At very low levels, the risk of death from any cause and from cardiovascular disease also increases. Their work also linked low testosterone levels to a higher risk of dementia and Alzheimer’s disease.
“Through the work we’ve done, we’re really aware that low testosterone is a pretty robust biomarker for poorer health outcomes, particularly in older men,” says Yeap, who has advised and received research support from companies that sell testosterone. But, he adds, the data does not justify testing asymptomatic men. “If you treat all men with low testosterone, will that actually prevent health problems? We haven’t proven that.”
Answering that question would require a large randomized clinical trial, potentially involving 10,000 older men with low testosterone and increased risk of poor health, followed for at least four years, Yeap says. His team is currently working to secure funding for such an initiative, which he says will be costly and complex. “But you have to get evidence,” he said. “You can’t just preemptively make assumptions, like some people might do.”
This article is reproduced with permission and has been published for the first time May 5, 2026.
