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Saw palmetto
Saw palmetto — what the European monograph actually supports, what it is not for, the form and how long it is meant to be used, side effects, and the 2 medicine interactions documented for it.
This is a reference page, not a diagnosis and not a prescription. Herbal products are real pharmacology: they have effects, side effects and interactions with medicines. Tell your doctor and your pharmacist everything you take, including teas and supplements, and never stop or change a prescribed medicine because of anything you read here.
What it is
Serenoa repens (W.Bartram) Small — fruit (Sabalis serrulatae fructus)
Grouped here under Joints, urinary tract and hormones. Regulatory position: EU herbal monograph covers lipophilic fruit extracts for urinary symptoms of benign prostate enlargement.
What the evidence supports
The registered indication: Relief of lower urinary tract symptoms related to benign prostatic hyperplasia, after a doctor has excluded serious conditions.
The best-known prostate supplement, and one of the clearest cases on this page of large trials disagreeing with popular use. Two large NIH-funded randomised trials — one reported in 2006, and a second in 2011 that escalated the amount up to triple the usual — found saw palmetto no better than placebo for the urinary symptoms of an enlarged prostate. European regulators still recognise particular lipophilic fruit extracts for the indication, and the extraction method matters a great deal to what is in the capsule, but the trials that carry the most weight do not support the effect. There is something more important than that argument, though. The symptoms it is bought for — weak stream, getting up at night, incomplete emptying — overlap with prostate cancer, bladder outlet problems, neurological disease and diabetes. Quietly self-treating them for a year is the real risk here, not the capsule.
D — Popular claim unsupported, or safety dominates The better trials are negative, or the substance appears in the literature mainly for the harm it has caused.
What it is not for
Urinary symptoms that have never been assessed, blood in the urine, inability to pass urine (a medical emergency), or prostate cancer.
Form, strength and how long
Lipophilic extracts of the dried fruit — hexane, ethanol or supercritical CO2 — in soft capsules. Powdered berry preparations are a different product and are not what the monograph describes.
Duration. Long-term use is the norm, which makes the requirement for an initial diagnosis more important, not less.
No gram figure appears on this page on purpose. The plant part, the extraction solvent and the drug-to-extract ratio together define a preparation, and a number taken from one does not describe another. The reasoning is set out on the hub; the amount that applies to you is the one printed on the pack you are holding, and a pharmacist will read it with you.
Side effects
Generally mild: stomach upset, headache, dizziness. Occasional reports of raised liver enzymes.
Who should avoid it
A men's product; not for women or children. Anyone due a PSA test or a urology appointment should say they take it.
Interactions with medicines
| Medicine or substance | What is described |
|---|---|
| Anticoagulants and antiplatelets (warfarin, DOACs, aspirin, clopidogrel) | Case reports of prolonged bleeding time and of bleeding events during surgery exist. With warfarin, a DOAC or antiplatelets, tell the prescriber. |
| Prescription medicines generally | Tell the doctor investigating your prostate that you take it, so results and symptom scores are read in context rather than in the dark. |
The reverse view — start from the medicine rather than the plant — is in the medicine, food and alcohol interactions reference, and summarised for every herb on this site.
Sources: European Medicines Agency — Committee on Herbal Medicinal Products (HMPC), European Union herbal monographs · NIH National Center for Complementary and Integrative Health — herb fact sheets · checked 2026-09-06
Frequently asked questions
What is saw palmetto used for?
Relief of lower urinary tract symptoms related to benign prostatic hyperplasia, after a doctor has excluded serious conditions. The best-known prostate supplement, and one of the clearest cases on this page of large trials disagreeing with popular use. Two large NIH-funded randomised trials — one reported in 2006, and a second in 2011 that escalated the amount up to triple the usual — found saw palmetto no better than placebo for the urinary symptoms of an enlarged prostate. European regulators still recognise particular lipophilic fruit extracts for the indication, and the extraction method matters a great deal to what is in the capsule, but the trials that carry the most weight do not support the effect. There is something more important than that argument, though. The symptoms it is bought for — weak stream, getting up at night, incomplete emptying — overlap with prostate cancer, bladder outlet problems, neurological disease and diabetes. Quietly self-treating them for a year is the real risk here, not the capsule.
Does saw palmetto work?
Graded D here: The better trials are negative, or the substance appears in the literature mainly for the harm it has caused. Urinary symptoms that have never been assessed, blood in the urine, inability to pass urine (a medical emergency), or prostate cancer.
How much saw palmetto should I take?
This reference does not print gram figures, because they do not transfer between preparations of different extract strength. What can be said honestly is the form and the duration: Lipophilic extracts of the dried fruit — hexane, ethanol or supercritical CO2 — in soft capsules. Powdered berry preparations are a different product and are not what the monograph describes. Long-term use is the norm, which makes the requirement for an initial diagnosis more important, not less.
What are the side effects of saw palmetto?
Generally mild: stomach upset, headache, dizziness. Occasional reports of raised liver enzymes.
Does saw palmetto interact with medicines?
Yes — documented for Anticoagulants, warfarin, Prescriptions. Each one is described on this page, with a link to the medicine-side reference where one exists.
Others in joints, urinary tract and hormones
Nettle
Leaf: to increase the amount of urine and so flush the urinary tract in minor complaints, and for minor joint pain. Root: lower urinary tract symptoms related to benign enlargement of the prostate.
Cranberry
Reducing the chance of repeat urinary tract infections in some groups — not treating an infection that is already present.
Black cohosh
Relief of menopausal complaints such as hot flushes and profuse sweating.
Devil's claw
Relief of minor joint pain, and of mild digestive complaints such as bloating and loss of appetite.
Feverfew
Prophylaxis of migraine headaches, after serious conditions have been excluded by a doctor.
Keep the whole list in one place
TempoLife logs supplements alongside food, sleep and how you actually felt — so the answer to "what are you taking?" is a screen, not a guess.