Intramuscular Testosterone Treatment in Elderly Men: Evidence of Memory Decline and Altered Brain Function

Context: Recent clinical trials of im testosterone in eugonadal men suggest positive effects on verbal memory, but other studies find no effect. Objective: Our objective was to determine whether supraphysiological testosterone influences verbal memory and brain function during a verbal memory task in healthy eugonadal older men. Patients, Design, and Setting: Fifteen cognitively normal men, aged 66–86 yr, participated in a randomized, double-blind, placebo-controlled crossover trial involving 9 months of participation per participant at a hospital-based research facility. Intervention: We used testosterone enanthate (200 mg im every other week for 90 d) crossed over with placebo (sesame oil vehicle im) with a 90-d washout between treatments. Main Outcome Measures: Performance was assessed on a standardized verbal memory test, and brain activity (relative glucose metabolic rates) in medial temporal and frontal regions was measured with positron emission tomography during a verbal memory task. Results: Trea...