JOSH*, 35, COULD easily go weeks—or even months—without sex. That is, until he started Mounjaro two years ago. Within a few months he’d lost 11 pounds, while gaining the raging libido and erections of a teenager.
David*, 75, meanwhile, had the opposite experience. A few weeks after starting Wegovy, his sexual desire plummeted and he had difficulty reaching an orgasm. These were temporary shifts that seemed to subside as the men continued on their GLP-1 medications.
Still, their stories are raising important questions that researchers are trying to untangle as the meds boom in popularity. In a 2025 Kinsey Institute survey, more than half of GLP-1 users reported that the medication had affected their sex lives—but the direction was divided: 16 percent said desire went down, while 18 percent said it went up, and 16 percent said sexual function improved while 12 percent said it worsened. What’s more, men were about twice as likely as women to report these shifts, either positive or negative.
GLP-1 usage quadrupling since 2024, it’s worth examining whether these changes can be blamed on the medications themselves—or merely the physical and physiological effects that come along with treatment. WELL, FIRST KNOW that clinical evidence is limited—and what does exist doesn’t exactly clear things up. In one 2025 observational study, semaglutide users were more likely to get a new erectile-dysfunction diagnosis or prescription.
But that’s correlational, not causational. Other studies have found that taking dulaglutide for four weeks had no effect on desire, and long-term dulaglutide use is associated with a slightly lower risk of moderate to severe erectile dysfunction. But the first study involved a small sample size and the second was funded by Eli Lily and Company, makers of the GLP-1 Zepbound, which raises possible conflict of interest concerns.
So we need more large-scale, independent research. Another wrinkle, according to Jay Luthar, MD, a Harvard-trained internist and founder of Lutanen Health: Liraglutide, semaglutide, and tirzepatide are often lumped together under the GLP-1 umbrella, but they’re not actually identical—so findings about one shouldn't automatically be applied to the others. WE KNOW THAT obesity and metabolic dysfunction can contribute to low testosterone and erectile challenges, and that GLP-1s may increase testosterone.
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