An editorial notes that “one important limitation of the study is a potential ceiling effect. Most participants were highly educated (>60% had some university education), and none had known cognitive dysfunction at baseline. These men probably had optimal cognitive function that could not be improved (ceiling effect) by any pharmacological intervention. Additionally, the absence of a decline in most cognitive tests in men in the placebo group suggests that the study was too short in duration, was underpowered, or used cognitive tests that were not sensitive enough to detect subtle changes in cognitive function. The study was powered post-hoc based on the number that would be needed to detect between-group differences in cognitive function (visual or verbal memory) that were as large or larger than the differences between men aged 75 years and older and those aged 50–59 years—a very high expectation for treatment effect in a 3 year study of men in their late 60s. Importantly, because of these limitations, the study does not address whether testosterone can prevent age-related decline in cognition in men, but only whether it can contribute to cognitive gains.”