Preliminary results from the Testosterone Trials, a group of studies supported in part by the National Institutes on Aging, suggest that restoring levels of testosterone to those of healthy young men improves the sexual function of seniors, but does not significantly affect mobility and fatigue.
The findings are from the first 3 of 7 double-blind, placebo-controlled trials aimed at determining whether testosterone treatment could alleviate those symptoms. The trials were recommended by the former Institute of Medicine (now the National Academy of Medicine) as a key step before considering larger trials of long-term risks.
In the studies, 790 men aged ≥ 65 years received daily testosterone or placebo via gel. Serum testosterone concentration was measured regularly for 12 months. Testosterone did not significantly affect walking ability, but in all 3 trials walking speed and distance did improve in the testosterone group, compared with the placebo group. Testosterone did not have a significant effect on fatigue, but had “modest favorable” effects on mood. Men in the testosterone group were also more likely to report that they had more energy.
“For a long time, there has been interest in whether testosterone is an appropriate therapy for aging-related conditions in men,” said NIA Director Richard Hodes, MD. “This study clarifies questions about some of its potential benefits. As the researchers note, clarifying the risks requires further study.” Participants experienced few adverse events, but too few to draw conclusions about risks in older men, especially given that men at high risk for prostate cancer and cardiovascular disease were not included in the trial.