Emmelot-Vonk, M. H., Verhaar, H. J., Pour, H. R., Aleman, A., Lock, T. M. Bosch, J. L., Grobbee, D. E., & van der Schouw, Y. T. (2008). Effect of testosterone supplementation on functional mobility, cognition, and other parameters in older men: A randomized controlled trial. JAMA Journal of the American Medical Association, 299, 39-52.

"Serum testosterone levels decline significantly with aging. Testosterone supplementation to older men might beneficially affect the aging processes".

This study investigated the effect of testosterone supplementation on functional mobility, cognitive function, bone mineral density, body composition, plasma lipids, quality of life, and safety parameters in older men with low-normal testosterone levels. Healthy men (N = 237) between the ages of 60 and 80 years with a testosterone level lower than 13.7 nmol/L were evaluated from January 2004 to April 2005 at a university medical center in the Netherlands. Ss were randomly assigned to receive 80 mg of testosterone undecenoate or a matching placebo twice daily for six months.

A total of 207 men completed the study. Lean body mass increased and fat mass decreased in the testosterone group compared with the placebo group. Those factors were not accompanied by an increase in functional mobility or muscle strength. Cognitive function and bone mineral density did not change. Insulin sensitivity improved but high-density lipoprotein cholesterol decreased. At the study end, 47.8% in the testosterone group vs. 35.5% in the placebo group had a metabolic syndrome. Quality-of-life measures were no different except for one hormone-related quality-of-life measure that improved. No negative effects on prostate safety were detected.

Implication. Over six months, testosterone supplementation to older men with a low-normal testosterone concentration did not affect functional status or cognition but increased lean body mass and had mixed metabolic effects. [If testosterone supplementation did not improve the function of males who needed it, what would its benefit be if administered to individuals who did not need it? This is but one more indication that testosterone supplementation has minimal effects on males and is almost certainly not related to improved movement or mental function.]

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