Men who used a gel to boost levels of testosterone did not increase their risk of heart problems in a large trial, researchers reported on Friday at the ENDO 2023 medical meeting.
There was also no increased risk for development of diabetes or diagnosis of prostate cancer associated with the testosterone gel, the researchers found.
Years ago, a small study suggested testosterone replacement therapy in men with low levels of the hormone might increase the long-term risks of heart disease, stroke or death. The U.S. Food and Drug Administration ordered manufacturers of testosterone pharmaceuticals to conduct a randomized, controlled trial to assess the safety of the treatment.
Researchers enrolled 5,246 men, ages 45 to 80, with a diagnosis of low testosterone who also had cardiovascular disease or were at high risk for it. They received either daily treatment with a testosterone gel from AbbVie or placebo gel for nearly two years, on average.
Roughly three years after the start of the study, the two groups had similar rates of cardiovascular events, defined as heart attack, stroke or heart-related death - 7.0% for the testosterone group and 7.3% for placebo - according to a report published in The New England Journal of Medicine.
Men treated with testosterone did have a higher rate of atrial fibrillation, kidney problems, and life-threatening blood clots in the lungs, along with a higher risk for fractures, researchers reported.
The trial results "should not be used as a justification for widespread prescription of these products to large numbers of men," senior author Dr. Steven Nissen of the Cleveland Clinic said in a statement.
And men should not attempt to treat low testosterone on their own, Nissen added.
"The market is booming with so-called 'natural' testosterone boosters," he said. "These products have not been evaluated in rigorous clinical trials and they have not been approved by the FDA to treat low testosterone levels."
The study was sponsored by AbbVie, Acerus Pharmaceuticals, Endo Pharmaceuticals, and Upsher–Smith Laboratories.