Testosterone therapy prevents gain in visceral adipose tissue and loss of skeletal muscle in nonobese aging men. Allan CA, Strauss BJG, Burger HG, Forbes EA, McLachlan RI. J Clin Endocrinol Metab 2008;93(1):139-146.
This Australian, double-blind, placebo-controlled 12-month study assessed the effect of the testosterone patch on total and regional body composition (using dual-energy X-ray absorptiometry and magnetic resonance imaging) and hormonal and metabolic indices in 60 healthy but symptomatic non-obese males aged ≥55 years with total testosterone <15 nmol/L.
Testosterone levels increased by 30% with testosterone (p<0.05) and fell by 10% with placebo (p<0.05). Bodyweight, body mass index and waist circumference did not change during treatment. Fat-free mass increased with testosterone and was unchanged with placebo (Figure); skeletal muscle mass followed the same trend (p=0.008). No changes in total body fat mass, regional fat mass, percentage body fat or abdominal subcutaneous fat were observed. Visceral adipose tissue mass decreased with testosterone and increased with placebo (p=0.001 for testosterone versus placebo); changes in visceral fat correlated with changes in testosterone levels (r2=0.36; p<0.05). A trend towards increased total and low-density lipoprotein cholesterol with placebo was noted.
No significant changes in haematocrit were observed. The dropout rate was high (30%).
Change in fat-free mass with testosterone patch or placebo. *p=0.026 for the between-group differences in change from baseline to 52 weeks.
Numerous studies have shown that topical testosterone reduces visceral fat. Many of these studies have included obese men, in whom the potential for fat reduction is even greater.
In non-obese men with low-normal testosterone levels, testosterone treatment significantly improved fat-free mass and skeletal muscle mass compared with placebo. The dropout rate was high (30%), as in other studies with the testosterone patch. This, and the small cohort size, was a limitation of this study.