AILSA CHANG, HOST:
Defense Secretary Pete Hegseth has announced that military members 30 and older will be screened annually for low testosterone.
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PETE HEGSETH: We owe our warriors the absolute best medical care in the world. And this program delivers on that obligation.
CHANG: But what is the science behind low testosterone? And could screenings and possible supplementation benefit service members? Well, those are the questions we're going to put now to Dr. Adriane Fugh-Berman, professor of pharmacology and physiology at Georgetown University. Welcome.
ADRIANE FUGH-BERMAN: Thank you.
CHANG: So how common of an issue is low testosterone in men in this age group? That is, 30 and older. What would you say?
FUGH-BERMAN: Well, it's actually quite rare. So testosterone should be replaced in men who have missing or injured testicles, but it's highly questionable whether anyone else should be treated.
CHANG: OK. Interesting. OK, well, how settled is the science on that? Like, when it comes to testing for testosterone levels, are these tests reliable? Is there a generally understood testosterone level that's considered normal?
FUGH-BERMAN: Well, so testosterone levels vary not only by age but also by activity. And they also vary hourly, daily, weekly, and they vary with different activities. Picking up a gun raises testosterone levels. Picking up a baby lowers testosterone levels. There have been studies in the military of people under simulated operations in which their testosterone levels go down, but then they rebound when they're getting enough rest and enough food. So...
CHANG: But if I could make the argument for the administration for just a moment, I mean, what is the data on how upping your testosterone level with replacement therapy could actually help some members of the military feel better? Like, is there data out there? Is there some conceivable basis for having a recommendation or doing these screenings?
FUGH-BERMAN: Not really. There is not good evidence that testosterone is associated with specific symptoms, and there's not good evidence that giving people testosterone will help those symptoms. It does increase mood. It does increase libido. In the doses that are used for, quote-unquote, "testosterone replacement therapy," it doesn't actually improve strength...
CHANG: Oh.
FUGH-BERMAN: ...In the doses that are used to actually treat low testosterone. And I think, importantly, these have adverse effects. Those...
CHANG: I was going to ask you, what are the possible risks of testosterone supplementation?
FUGH-BERMAN: Yeah. The treatment can cause blood clots, heart problems, kidney problems, fractures, infertility and shrunken testicles as well.
CHANG: Ooh.
FUGH-BERMAN: Yeah.
CHANG: Well, when it comes to heart complications, I saw, like, in 2023, the Cleveland Clinic provided some reassurance about that, about at least the risk of death from cardiac problems. Essentially, their study found no appreciable increase in risk when testosterone is prescribed appropriately.
FUGH-BERMAN: So that was a short-term study of older men with quite low testosterone levels who were very carefully monitored and brought up to only a very reasonable level of testosterone. We don't know anything about the long-term risks. And that is the same study - if you're talking about the TRAVERSE study - that found an unexpected increase in fractures. So testosterone actually increases bone mass, so it makes the bones thicker, but it also makes them more fragile, apparently.
CHANG: Well, is there something else that you would recommend as a physician that the military do to best care for the health of its service members?
FUGH-BERMAN: Well, absolutely. Treating underlying chronic conditions is important. You want to make sure that you're actually treating high blood pressure and high cholesterol and diabetes. And also, because military people are often living in very close quarters, a robust vaccination program is also important. The military had made flu vaccinations optional and had an epidemic of flu, and they reversed that decision. Hopefully, they'll do the same thing with testosterone.
CHANG: Dr. Adriane Fugh-Berman, professor of pharmacology and physiology at Georgetown University, thank you very much.
FUGH-BERMAN: Thank you. Transcript provided by NPR, Copyright NPR.
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