Saw palmetto, an over-the-counter herbal therapy used by more than 2 million men for symptoms of an enlarged prostate, may be no more effective than a placebo, according to a study published in this week's issue of The New England Journal of Medicine.
The study followed 225 men who had moderate-to-severe symptoms of an enlarged prostate, also known as benign prostatic hyperplasia, or BPH. Half of the men were given saw palmetto extract twice a day, and half were given an inactive medication, or placebo.
At the end of one year, the men taking saw palmetto showed no significant improvement in their symptoms, nor did the placebo group.
The findings were welcomed by some doctors who said they felt all along that saw palmetto didn't work.
Dr. Jacques Carter, at Beth Israel Deaconess Medical Center in Boston, said he has observed in his own clinical practice that saw palmetto is virtually ineffective.
"In nearly every instance, my patients reported little if any improvement of the symptoms on this supplement," Carter said.
And Dr. Carl Reese, at Pennsylvania State University College of Medicine, hopes the new finding can convince patients to stop spending money on saw palmetto.
"Millions of dollars are spent each year by men on this product and it may not be of any benefit," said Reese. "This article will help the argument that they are wasting their money."
Although the findings suggest that saw palmetto is not effective, the supplement is not known to cause harm. The symptoms of an enlarged prostate include difficulty urinating, a weak urine stream or frequent urination at night. It is an aggravating but otherwise harmless disorder that affects mostly older men.
Some doctors do recommend saw palmetto to their patients and still will, despite this new findings.
In his clinical practice, Dr. Aaron Katz, director of he Center for Holistic Urology at Columbia University in New York, said he probably has more than 200 patients on saw palmetto.
"My impression is that this herbal compound can still help and prevent many men from having symptoms of [enlarged prostate]," he said.
Katz and other doctors said they would like to see more data on the supplement before they change their minds about recommending it to their patients.
Doctors say there are many preparations of saw palmetto, and as with most supplements, not every preparation is exactly the same. It's possible that other preparations of saw palmetto might be effective, even though the one used in this study was not.
Dr. David Crawford, at the University of Colorado, is a principal investigator for the Complementary and Alternative Medicine for Urological Symptoms Clinical trial, a government-sponsored study that asks whether saw palmetto affects the clinical progression of BPH.
Crawford agrees that this study questions the value of saw palmetto but said more studies need to be done.
"This is a nail in the coffin but it's not shut," he said.