Six-week improvements in muscle mass and strength during androgen therapy in older men

The purpose of our study was to assess the early effects of a potent anabolic androgen on muscle mass and strength, lower extremity power, and functional performance in older men.

Thirty-two men 72 +/- 6 years of age were randomized to receive oxandrolone (10 mg twice daily) or matching placebo in a 2:1 manner for 12 weeks. Total and appendicular lean body mass (LBM) were assessed by dual-energy x-ray absorptiometry (DEXA). Lower extremity muscle volume was determined by magnetic resonance imaging to validate DEXA changes.

Total LBM increased by 2.7 +/- 1.6 kg after 6 weeks with oxandrolone (p <.001), which was greater (p <.001) than the decline in LBM (-0.5 +/- 0.9 kg) with placebo. Appendicular LBM increased by 1.2 +/- 0.9 kg after just 6 weeks with oxandrolone (p <.001), which was greater (p <.001) than the decline in LBM (-0.4 +/- 0.5 kg) with placebo. These changes were >90% of the gains in total and appendicular LBM (3.0 +/- 1.5 kg and 1.3 +/- 0.9 kg, respectively) after 12 weeks. Total thigh and hamstring muscle volume increased by 111 +/- 29 mm(3) (p =.001) and 75 +/- 18 mm(3) (p =.001), respectively, after 12 weeks. Maximal strength increased for the leg press 6.3 +/- 5.6% (p =.003), leg curl 6.7 +/- 8.6% (p =.01), chest press 6.9 +/- 6.5% (p =.001), and latissimus pull-down 4.8 +/- 6.3% (p =.009) with oxandrolone after 6 weeks; these increases were different than those with placebo (p <.001) and were 93%, 96%, 74%, and 94% of the respective gains at week 12. There were no improvements in functional measures.

Treatment with a potent anabolic androgen may produce significant increases in muscle mass and strength after only 6 weeks in healthy older men. However, such treatment did not improve leg muscle power or walking speed.