Ask the Doctors by Eve Glazier, M.D. and Elizabeth Ko, M.D

Man Looking for Natural Remedies to Relieve an Enlarged Prostate

Dear Doctor: Now that I'm in my 60s, with an enlarged prostate, I'm noticing ads and solicitations offering the latest and greatest herbal remedies for my prostate health, such as saw palmetto. Do any of these remedies actually work?

Dear Reader: Undoubtedly, you want relief. The much-maligned prostate gland is necessary throughout a man's life for sexual function, but it's generally discussed only as a man ages and it becomes cancerous or, in your case, enlarged. Because the prostate sits at the lower end of the bladder and surrounds the urethra, this enlargement can cause obstruction of urinary flow. This, in turn, causes a slow urinary stream, hesitancy and straining with urination, frequent urination and the need to get up multiple times during the night to urinate.

Many over-the-counter prostate products contain saw palmetto (Serenoa repens), a species of dwarf palm tree that bears fruit. Extracts from the fruit have been used in supplements as far back as ancient Egyptian times to help men with urinary symptoms, and they may work for many possible reasons. For starters, they can inhibit the formation of the prostate-stimulation hormone, dihydrotestosterone, in a way similar to prescription medications Avodart and Proscar. Saw palmetto also may relax the muscles at the lower portion of the bladder, allowing the urine to empty more completely, and may shrink prostate size due to an anti-inflammatory effect.

A 1998 review in the Journal of the American Medical Association analyzed 18 saw palmetto studies involving 2,939 men. The average length of the studies was nine weeks. Among men who took the supplement, the authors found a decrease in urinary frequency and nighttime awakening to urinate, plus an improvement in urine flow. The results were similar to those for the prostate drug Proscar.

But results of a 2012 review using data from different medical sources were more mixed. In 32 studies involving 5,076 men using either saw palmetto or a placebo, some studies showed benefit, but not all. The average length of these studies was 29 weeks. The authors concluded that, in general, saw palmetto did not show a significant degree of benefit. Note, however, that one proprietary blend, called Permixon, has shown benefit in multiple European studies.

My opinion is that saw palmetto likely does have a mild beneficial effect. The biggest side effect can be a decrease in libido.

Now let's take look at other supplements touted for prostate health.

Stinging nettle (Urtica dioica) has been shown to shrink prostate size in rats, and a 2005 placebo-controlled study of 620 men in Iran linked the herb to an improvement of urinary flow and less urine retention in the bladder. These results have not been replicated in other studies, however.

Pumpkin seed oil has shown benefit in rats, but no good studies have been done in humans.

Selenium -- at higher levels in the bloodstream -- has been associated with a lower risk of prostate cancer. However, no good studies of selenium and prostate enlargement are available.

Ginger may decrease prostate size, but -- again -- no good studies have shown that it reduces symptoms in humans.

Lastly, vitamin E, which had been used in many supplements, has been linked to an increase in the risk of prostate cancer.

The upshot? Although many supplements and vitamins may benefit the prostate, they can have side effects and need to be studied further.

(Send your questions to, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)