Testosterone supplementation shows limited benefit for mobility, cognition

Older men with low testosterone levels who received testosterone supplementation increased lean body mass and decreased body fat, but were no stronger and had no improvement in mobility or cognition compared with men who did not use the supplement, according to a study published in JAMA (2008; 299:39-52).

Researchers led by Marielle H. Emmelot-Vonk, MD, of University Medical Center Utrecht, the Netherlands, conducted a randomized, placebo-controlled study to assess the effects of testosterone supplementation on functional mobility, cognition, bone mineral density, body composition, lipids, quality of life, and safety parameters in older men with testosterone levels less than 13.7 nmol/L during a period of 6 months. The trial included 207 men between the ages of 60 and 80 years. Participants were randomly assigned to receive testosterone undecenoate, 80 mg, or a matching placebo twice daily for 6 months.

During the study, lean body mass increased and fat mass decreased in the testosterone group compared with the placebo group, but these factors were not accompanied by an increase of functional mobility or muscle strength. Cognitive function and bone mineral density did not change. Insulin sensitivity improved, but high-density lipoprotein cholesterol decreased.

Quality of life measures did not differ aside from hormone-related quality of life in the testosterone group. Adverse events were not significantly different in the two groups. Testosterone supplementation was associated with an increase in the concentrations of blood creatinine, and hemoglobin and hematocrit. No negative effects on prostate safety were detected.

“This study is, as far as we know, the largest study of testosterone supplementation with the most endpoints and a randomized, double-blind design. Adherence was high and the dropout rate was low,” the authors wrote. “The findings in this study do not support a net benefit on several indicators of health, functional, and cognitive performance with 6 months of modest testosterone supplementation in healthy men with circulating testosterone levels in the lower range.”