Because of Urtica Dioica...taken from the M-Test right-up thread...
Urtica Dioica has been shown by researchers to be beneficial for prostate health [8]. Dihydrotestosterone (DHT), a metabolite of testosterone, can stimulate prostate growth which can lead to a variety of negative issues including prostate problems and hair loss [8]. Urtica Dioica contains components that may inhibit the binding of DHT to various sites around the prostate membrane thereby helping prevent benign prostatic hyperplasia [7]. Also, Urtica Dioica may help inhibit an enzyme known as 5-alpha reductase. This enzyme is responsible for conversion of testosterone into dihydrotestosterone (DHT) [5, 8].