
Testosterone therapy improves body composition and quality of life in men with late-onset hypogonadism: A large, randomized, placebo-controlled study. Bouloux P-M, Kelly J, Hiemeyer F. The Aging Male 2008; 11(1):1-41.
Key Points
This multi-centre, double-blind placebo-controlled study assessed the efficacy and safety of Testogel® (1% testosterone gel) in 352 men aged 50-80 years with late-onset hypogonadism.
The primary outcome measure was change from baseline to 6 months in lean body mass (assessed using dual-energy X-ray absorptiometry). Fat mass, total body mass, health-related quality of life (assessed using the Aging Males’ Symptoms Scale [AMS]) and serum lipid levels were also assessed.
The increase in lean body mass was significantly greater with testosterone than placebo (Figure). This increase occurred irrespective of age and baseline serum total testosterone levels. Fat mass decreased by 1.13 kg with testosterone and 0.09 kg with placebo (Figure). No significant changes in total body mass were observed with either testosterone or placebo. Significant improvements in quality of life scores were observed with testosterone (-10.8) compared with placebo (-6.9; p<0.05). Improvements in lipid parameters were also noted. No unexpected safety concerns arose during the study.
Change in lean body mass and fat mass with testosterone and placebo. *p<0.0001 versus placebo.

The links between low testosterone and increased visceral fat are well established, as are the improvements with therapy, particularly depot injection. Improvements in AMS and sexual function scores with testosterone therapy have been observed in a number of studies. Another large-scale study of 2% testosterone gel suggested that it may take 12 months before metabolic changes reach statistical significance.1
This is the largest published study of 1% testosterone gel with changes in body composition as primary endpoint. Improvements in AMS scores were similar to those observed in other studies. The reduction in total and LDL cholesterol was greater than that observed in other studies, even compared with a cohort exposed to aggressive primary care lipid management. The 6-month study duration meant that it was not possible to assess whether these benefits were more marked at 12 months, as has been observed in other studies. However, the study had a total duration of 18 months and further results will be published later. The safety data again showed no cause for concern in terms of prostate or haematocrit.
References
1. Jones H, et al "Testosterone improves glycaemic control, insulin resistance, body fat and sexual function in men with the metabolic syndrome and /or type 2 diabetes: a Multicentre European Clinical Trial: the TIMES2 Study" BES 2010; 21: OC1.6.