Saw palmetto is a traditional herbal remedy used to relieve the symptoms of urinary tract discomfort in men with an enlarged prostate or BPH.
Saw palmetto is registered by the Medicines and Healthcare products Regulatory Agency (MHRA) for sale in the UK as a traditional herbal remedy. However, registration is based on traditional use and manufacturing quality rather than on the results of clinical studies.
A number of studies have shown an improvement in symptoms of enlarged prostate. They have shown it can reduce the need to urinate in the night and improve urinary flow. For instance, one US review of studies on the subject conducted in 2000 and published in the Journal of Urology concluded: "Evidence suggests that saw palmetto may have a significant effect on urinary flow rates and symptom scores compared to placebo in men with lower urinary tract symptoms."
Results are mixed, however. For instance, in one 2006 double blind trial published in the New England Journal of Medicine, researchers studied 225 men with moderate to severe BPH. They found no significant difference between symptoms in the saw palmetto and placebo groups.
Laboratory studies suggest that saw palmetto lowers the levels of male sex hormones. While prostate cancer can be affected by these hormones, there's no evidence that saw palmetto is an effective treatment for it.
Other studies of saw palmetto - for baldness, general swelling and bladder problems - have had inconclusive results.
Saw palmetto dose and instructions for use
Follow the instructions on the pack. Remember to seek medical advice before taking any supplement, as they can interfere with other treatments.
Saw palmetto food sources
There are no food sources of saw palmetto.
Saw palmetto supplement information
Like any supplement, keep saw palmetto supplements in a cool, dry place, away from humidity and direct sunlight.
Saw palmetto warnings
- Side effects are uncommon and typically mild. The most common are nausea, stomach pain, bad breath, constipation, diarrhoea and vomiting. Men taking saw palmetto have also reported erection problems, testicular pain and tenderness in the breasts.
- Interactions. If you take any medicines regularly, talk to your GP before you start using saw palmetto supplements because they could interact with medicines like aspirin, NSAID painkillers (such as ibuprofen), blood thinners and hormone treatments. In combination with ginkgo biloba or garlic, saw palmetto might seriously increase the risk of bleeding.
- Risks. People who have chronic diseases or health conditions should not use saw palmetto without talking to their GP first. There is some concern that saw palmetto might interfere with men's PSA (prostate-specific antigen) levels, the test used to help diagnose and monitor prostate cancer. Talk to your GP about this issue.
Given the lack of evidence about its safety, saw palmetto is not recommended for children or for women who are pregnant or breastfeeding.