Emmelot-Vonk, M. H., Verhaar, H. J., Nakhai Pour, H. R., Aleman, A., Lock, T. M., Ruud 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.

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[This study uses individuals with low testosterone levels as Ss. The effects of augmentation of testosterone levels likely would be emphasized in Ss with a deficiency when compared to Ss with no deficiency. In Ss with no deficiency, excess testosterone is expelled and/or the body ceases to produce testosterone. Consequently, this investigation shows what would happen when testosterone supplements existing levels (as often is the case in females) rather than replacing normal testosterone.]

The effects of prolonged 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 were investigated. Ss were healthy men (N = 237; 60-80 years) with a testosterone level lower than 13.7 nmol/l. Ss were randomly assigned to receive 80 mg of testosterone undecenoate or a matching placebo twice daily for 6 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 but those factors were not accompanied by increases in functional mobility or muscle strength. Cognitive function and bone mineral density did not change. 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. Testosterone supplementation in older men with a low normal testosterone concentration over six months did not affect functional status or cognition but increased lean body mass and had mixed metabolic effects. In the sample that would be likely to benefit from testosterone supplementation, effects were minor and non-functional.

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