It is also known that prostatic levels of dihydrotestosterone (DHT) as well as the androgen receptor remain high with aging, despite the fact that peripheral levels of testosterone are decreasing with age. Moreover, androgen withdrawal leads to partial involution of established BPH.5 Assuming normal ranges, there is no clear relationship between the concentration of circulating androgens and prostate size in aging men or more specifically in men with BPH enrolled in clinical trials