saw palmetto

Saw palmetto is a dietary supplement made from the berries of Serenoa repens, a small palm native to the southeastern United States and the West Indies. The berry extract is sold in capsule, tablet, and liquid forms.

Despite its popularity, current research does not support saw palmetto for the conditions people commonly use it for. NCCIH notes that NIH-funded trials (including one testing up to about three times the usual dose) and a Cochrane review found that saw palmetto was no more effective than placebo for the urinary symptoms of BPH. A 2023 review of 27 studies concluded that the herb, when taken alone, "provides little or no benefit for BPH symptoms." A separate review found no significant benefit for chronic prostatitis, and NCCIH describes the evidence for hair loss as too limited to draw conclusions.

There is no established effective dose, because studies have not shown a clear benefit for the conditions saw palmetto is used for. Trials commonly tested 320 mg of standardized berry extract daily, and some tested up to roughly two to three times that amount without showing improvement. Because it has not been shown to work for these conditions, talk to your doctor or pharmacist before using it — and especially before relying on it in place of a proven treatment for prostate or urinary symptoms.

According to NCCIH, saw palmetto appears to be well tolerated by most people and has been used safely in research studies lasting up to three years. It does not appear to affect PSA (prostate-specific antigen) blood test readings. It may be unsafe during pregnancy or breastfeeding, and safety data for women and children are limited. Talk with your healthcare provider before use, particularly if you have a prostate condition.

NCCIH describes side effects as usually mild and infrequent. Reported effects include stomach or digestive discomfort, dizziness, and headache.

NCCIH reports that saw palmetto has not been shown to interact with medications. Even so, herbs and medicines can sometimes interact in harmful ways, so tell your healthcare provider about any supplements you take — particularly if you use blood thinners or are scheduled for surgery.