Androgen drives many prostate cancers. But the body uses androgen for muscle growth and maintenance, among other functions. An ongoing study evaluates the effects of androgen deprivation therapy not just on patients’ physical function but on global geriatric health, including skills of daily living. Because the study is longitudinal, following individual patients from before treatment through the course of their care, findings can help to define not only the characteristics of men who will need supportive care, but when in treatment this care should begin.