Testosterone intake and aggressiveness: Real effect or anticipation?

In a double-blind experiment, human males (n = 27) were given either testosterone (40 mg/day), placebo, or no treatment, over a one week period. Subjective and observer assessed mood estimations were conducted before and after treatment. Testosterone levels in saliva were measured with radioimmunoassay. The results revealed a significant placebo effect [c. f. Medicine and Science in Sports 4: 124–126]: After treatment, the placebo group scored higher than both the testosterone and the control group on self-estimated anger, irritation, impulsivity, and frustration. Observer-estimated mood yielded similar results. The lack of a placebo effect in the testosterone group is intriguing, and may be due to secondary effects caused by suppression of the body's own testosterone production, since recorded non-protein bound testosterone did not significantly rise due to treatment. The resultss suggest that androgen usage causes expectations, rather than an actual increase of aggressiveness.