Although it is native to the United States, saw palmetto, like other alternative medicines, first became popular in Europe, where herbal remedies are big sellers.

In many European countries, a number of prescription and over-the-counter remedies for prostate enlargement contain saw palmetto extract. In Germany, for example, saw palmetto is an approved drug often recommended by physicians. This is because using saw palmetto to treat an enlarged prostate can be quite effective. Now saw palmetto is also very popular in the United States.

Saw Palmetto Studies

In Belgium, researchers gave saw palmetto extract to 505 men with benign prostate disease. At the end of the trial, the researchers concluded that saw palmetto had aided urinary flow, reduced residual urinary volume and prostate size, and otherwise improved the patients' quality of life. Saw palmetto, moreover, began to produce results within 45 days. Finasteride, on the other hand, can take six months to a year to work, if indeed it works at all.

After 90 days of saw palmetto treatment, 88 percent of patients and their physicians said they considered the therapy to be effective. Said the Belgian researchers: "The extract of saw palmetto appears to be an effective and well-tolerated pharmacologic agent in treating urinary problems accompanying benign prostate hypertrophy."

In a two-year study conducted in Germany, 88 men with mild BPH were randomly assigned saw palmetto or placebo (dummy pill). By the end of the study, the men taking saw palmetto were much less likely to have had their symptoms worsen compared to those men who were on the placebo.

But not all the studies of saw palmetto have been as encouraging. In one double-blind trial, 110 patients took either a placebo or an extract of saw palmetto for one month. The patients who received saw palmetto showed statistical improvement, but not enough for the researchers to conclude that saw palmetto was an effective treatment.

A very large trial published in the New England Journal of Medicine in 2006 found no effect for saw palmetto compared to placebo. However, the men in this study had significantly more severe BPH symptoms than in previous studies. This research seemed to confirm that saw palmetto is best for mild-to-moderate BPH symptoms and is unlikely to help in more serious cases.

How Saw Palmetto Works

According to the late pharmacognosist Varro E. Tyler, Ph.D., former professor emeritus at Purdue University School of Pharmacy in Indiana, an extract from saw palmetto berries appears to counteract the effects of certain male sex hormones, called androgens, that may cause prostate enlargement. He said it also has an anti-inflammatory activity.

Just how saw palmetto achieves results remains unclear. Studies in mice have shown that an extract of saw palmetto berries inhibits the enzyme 5-alpha-reductase. That's the chemical, you'll recall, that spurs production of DHT, which causes prostate tissue growth.

Saw palmetto extract also appears to inhibit DHT from binding to cell receptor sites. This increases the breakdown of DHT and encourages its excretion. Other studies show saw palmetto can relax the prostate tissue by blocking the same receptors as alpha-blockers like tamsulosin.

Other research suggests saw palmetto appears to reduce the effects of excess estrogen. In a subsequent human trial, 80 percent of men with benign prostate enlargement reported significant improvement in symptoms after using saw palmetto extract.

How Does Saw Palmetto Compare?

Medications used to treat BPH typically cost twice as much (or more) as saw palmetto. Prices vary from region to region, but as far back as 1993, the U.S. Office of Alternative Medicine concluded that $2.78 billion per year could be saved by using saw palmetto more widely. The savings would certainly be much more today.

Nonetheless, it's unlikely that you'll see saw palmetto as a federally approved drug any time soon. In 1990, a company called Enzymatic Therapy petitioned the FDA to have saw palmetto approved for treatment of BPH. The federal agency rejected the application. FDA officials said they recognized results of clinical trials that showed "statistically significant" improvements in men who took the herbal extract. But the FDA concluded that such data was not "clinically significant."

What Should You Take?

So where does that leave you if you're suffering from symptoms of prostate enlargement? The first thing to do is to see your doctor to rule out other conditions, including prostate cancer. Then the two of you can determine whether it would be in your best interest to try prescription medications, saw palmetto extract, or a combination to treat your enlarged prostate.

When purchasing saw palmetto, be sure to buy an extract standardized to contain 85 to 95 percent fatty acids and sterols. Berries alone, although cheaper than the extract, would have to be taken in much greater amounts to achieve beneficial effects. Only standardized fatty acid sterols have been studied for their ability to shrink prostatic tissue.

As discussed in this article, there are many steps you can take on your own to ease the symptoms of an enlarged prostate. But remember to see your doctor regularly -- don't let an enlarged prostate go untreated.

For more information, see 5 Home Remedies for Prostate Problems about learn more about prostate health on the next page.