By the age of fifty, about 30% of men will start to experience difficulties with urination related to enlargement of the prostate gland, also known as benign prostatic hypertrophy (BPH). These symptoms often lead to an increased sense of frustration and embarrassment, as well as the disruption of normal activities. Enlargement of the prostate is usually caused by an abnormal overgrowth and/or swelling of the tissue of the prostate, which then blocks the urethra or opening from the bladder. Problems associated with this condition usually continue to worsen with age, increasing in incidence to about 50% of males by the age of sixty, and up to almost 80% past age seventy. Most physicians consider this to be a normal consequence of aging.

Throughout their lives, men produce both testosterone, an important male hormone, and small amounts of estrogen, a female hormone. As men age, the amount of active testosterone in the blood decreases, leaving a higher proportion of estrogen. Studies done with animals have suggested that BPH may occur because the higher amount of estrogen within the gland increases the activity of substances that promote cell growth.

Another theory focuses on dihydrotestosterone (DHT), a substance derived from testosterone in the prostate, which more actively stimulates prostate growth. Most animals lose their ability to produce DHT as they age. However, some research has indicated that even with a drop in the blood's testosterone level, older men continue to produce and accumulate high levels of DHT in the prostate. Scientists have also noted that men who do not produce DHT do not develop BPH. 5-alpha reductase is the enzyme which converts testosterone to dihydrotestosterone (DHT) which, besides stimulating prostate growth is the hormone that triggers androgenetic alopecia in individuals who are genetically susceptible.

Some researchers suggest that BPH may develop as a result of "instructions" given to cells early in life. According to this theory, BPH occurs because cells in one section of the gland follow these instructions and "reawaken" later in life. These "reawakened" cells then deliver signals to other cells in the gland, instructing them to grow or making them more sensitive to hormones that influence growth.

There appears to be little or no connection between BPH and prostate cancer development. PSA, a lab test for detecting prostate cancer can occasionally be elevated in BPH also.

Several natural treatments have been found to be very useful in preventing and treating BPH. Some products contain combinations of beneficial agents and as such may be more effective.