There is an enzyme that converts testosterone to dihydrotestosterone. Dihydrotestosterone is associated with hair loss, prostate enlargement, loss of bladder function, increased risk of prostate cancer and angina. You need some dihydrotestosterone but not too little or too much. The enzyme that converts testosterone to dihydrotestosterone is called 5-alpha reductase. There are many factors that inhibit that enzyme including zinc and progesterone. Therefore by controlling the dihydrotestosterone levels you can decrease frequency of hair loss and urinary symptoms such as urinary frequency dribbling, the need to urinate throughout the night, and poor urinary stream etc. This is why it is so important to maintain the level of DHT (Progesterone inhibits DHT) because DHT has growth promoting effects on prostate cells that is greater than that of testosterone by 2.4-10 times. For low progesterone use ProgX.