Exactly how saw palmetto was thought to relieve the symptoms is unclear, but the fruit of saw palmetto dwarf palm tree remains widely used.

Now, a new study shows that this popular remedy is no more effective than a placebo or dummy pill at relieving these symptoms — even in high doses.

The study is published in The Journal of the American Medical Association.

The technical name for an enlarged prostate gland is benign prostatic hyperplasia (BPH).

Symptoms of BPH include:

Trouble with urination

Weak urine stream

Frequent urination, especially at night

Not feeling empty after urination

As a result, men run the risk of developing urinary tract infections and/or needing surgery because of a blockage of urine flow.

Saw Palmetto or Rx Drugs?

So should men skip the saw palmetto and go right to prescription medications?

Not so fast. “There is no real downside to taking saw palmetto, but the patient forgoes treatment that we know works,” says researcher Gerald Andriole, MD. He is the Robert K. Royce distinguished professor and chief of urologic surgery at Washington University School of Medicine in St. Louis.

Certain prescription medications can help treat the symptoms of an enlarged prostate. These include alpha blockers such as Cardura (doxazosin), Flomax (tamsulosin), Hytrin (terazosin), and Uroxatral (alfuzosin). These drugs help relax the prostate muscle tissue to increase the flow of urine.

Another category of drugs to treat BPH are 5-alpha reductase inhibitors. These include Avodart (dutasteride) and Proscar (finasteride). They help shrink the enlarged prostate and may prevent further growth. Both types of drugs do have risks.

Some men will need surgery to relieve the symptoms associated with an enlarged prostate.

“Proven therapies prevent urinary retention and the need for surgery and help reduce the chances of developing a urinary tract infection,” Andriole says.

But according to the new study, “men are at the same risk for these events if they take saw palmetto as someone with placebo.”

The study included more than 300 men aged 45 and older who had moderate symptoms of an enlarged prostate. Men in the study either took saw palmetto extract starting at 320 milligrams or a placebo. The study lasted 72 weeks. Men took increasing doses of saw palmetto extract over time — up to three times the standard dose of saw palmetto or 960 milligrams.

Men in both groups — the saw palmetto and placebo — improved slightly.

Put another way: the placebo was just as effective as the saw palmetto at relieving prostate problems such as frequent urination.

“We made an effort to really push near maximum reasonable doses, and at least this particular penetration doesn’t make any difference,” Andriole says.

The saw palmetto supplement used in the study was supplied by a single manufacturer. Whether or not the findings can be applied to other available brands or preparations of saw palmetto is not known, he says.

Second Opinion

Elizabeth Kavaler, MD, a urologist at Lenox Hill Hospital in New York City, says that there is no real downside to trying saw palmetto.

Saw palmetto may not help, but it also can’t hurt, at least not directly, she says.

“If the saw palmetto doesn’t work, you could end up in the emergency room for your symptoms,” she says. Another issue is that supplements are not regulated in the same way as prescription medications are, so you can’t always be sure what you are getting, Kavaler says.

“Saw palmetto still has a place in supporting some men,” says Duffy MacKay, ND. He is vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a trade group representing the dietary supplement industry.

Both groups of men did see an improvement, he says.

Saw palmetto and other botanicals do not produce an “immediate and dramatic” effect, MacKay says. “People need to manage their expectations and things like saw palmetto should be combined with weight loss, exercise, and some therapies targeted at inflammation when treating BPH.”

Inflammation may play a role in causing an enlarged prostate gland, he says.

Saw palmetto may be worth a try, MacKay says. “If you are not getting the results that you want, take the next step, which is likely a stronger prescription medication that will have a faster effect, but it is not without risk.”