Saw palmetto (Serenoa repens) is a small palm plant native to the southeastern United States. Traditionally it was used to treat a variety of conditions, including reproductive issues and coughs. Today, it is mainly recommended to treat symptoms of benign prostate hyperplasia (BPH), commonly known as enlarged prostate. These include frequent urination (more than 8 times per day), urinary urgency, weak or interrupted urine stream, and painful urination. BPH is estimated to affect as many as 14 million men in the U.S. alone.
Studies have produced conflicting results as to the efficacy of saw palmetto in treating symptoms of BPH. Some research has shown that it’s as effective as prescription drugs in treating symptoms of BPH, while others have shown that it’s no better than placebo. A 2019 research review published in Food Science and Biotechnology suggested a reason for these discrepancies. “In conclusion,” the reviewers wrote, “saw palmetto extract (SPE) has therapeutic potential. However, the efficacy of SPE has been found to be inconsistent, at least partly due to a lack of standardization of the SPE formula.”
Now, a study published in the Journal of Urology Open Plus in August highlights this issue of standardization, finding that only 25 percent of saw palmetto products tested met the potency standards thought to be effective in treating BPH symptoms.
American and Canadian researchers purchased 28 saw palmetto products—including berry powders, extracts, blends, and multi-actives—from popular online and retail stores. The products were then blindly tested using gas chromatography to assess their total fatty acid content and individual fatty acid profiles (the bioactive constituents of SPE) and compared to the US Pharmacopeia’s standards for saw palmetto.
Of the 28 supplements included in the study, only seven were found to have the appropriate dosage of 320 milligrams of saw palmetto extract and the minimum 80% fatty acids shown to address inflammation and improve symptoms of BPH. Total fatty acid content ranged from 0.796% for a berry powder product to 89.923% for a lipid extract product. None of the berry powders met the criteria for clinical efficacy, while six of nine lipid extracts, and one multi-active product met the criteria for total fatty acid content.
“This study not only confirms the rampant variability of saw palmetto products, but also highlights the need for physicians and industry to verify the quality of the supplements they’re recommending to patients and consumers to ensure the best results possible,” said the study’s lead author, Bilal Chughtai, MD, of the urology department at Weil Cornell Medicine.
Based on their tests, Chughtai and his colleagues emphasize three criteria that make up a quality saw palmetto product. “Specifically, clinicians and patients should select only products labeled with the following 3 criteria: (1) saw palmetto berry extract (S. repens, not Serenoa serrulata); (2) standardized to ≥80% FAs; (3) dosage regimen of one 320 mg or two 160 mg capsules/softgels per day,” they wrote in their conclusion.