Prostate health
Saw Palmetto and the Prostate: What the NIH Trials Really Found
Saw palmetto did not improve enlarged prostate (BPH) symptoms in two NIH-funded trials, and a 2023 review of 27 studies found little or no benefit, says NCCIH. Trials used 320 mg a day. SodaPeak lists saw palmetto third in a 1,200 mg blend, so it holds at most 400 mg per 2 capsules.
Written by the SodaPeak editorial teamUpdated · 9 min read
The evidence
Does saw palmetto help an enlarged prostate?
Probably not much. The National Center for Complementary and Integrative Health (NCCIH) says a 2023 review of 27 studies found that saw palmetto alone provides little or no benefit for symptoms of an enlarged prostate (NCCIH: Saw palmetto).
An enlarged prostate is called benign prostatic hyperplasia, or BPH. It is not cancer. It can squeeze the tube that carries urine, so men get up at night, feel a weak stream or feel they never fully empty.
Saw palmetto is the berry of a small palm from the southeastern United States. It has been sold for prostate and urinary symptoms for decades. Popular use is not the same as proof, and the best trials point the other way.
The trials
What did the NIH saw palmetto trials show?
Both NIH-funded trials found that saw palmetto did not improve BPH symptoms compared with a placebo pill. One used the standard dose; the other raised it to three times the usual amount, according to NCCIH (NCCIH: Saw palmetto).
| Study | Dose | Length or size | Result |
|---|---|---|---|
| NIH-funded trial (2006) | 160 mg twice a day | 225 men, 1 year | No difference from placebo in symptoms, urine flow, prostate size or quality of life (LiverTox: Saw palmetto) |
| Second NIH-funded trial | Raised up to 3 times the usual dose | Dose stepped up over time | Did not improve BPH symptoms (NCCIH: Saw palmetto) |
| 2023 review | Various | 27 studies | Little or no benefit when used alone (NCCIH: Saw palmetto) |
| Other trials | 320 mg once a day | Various | The common study dose, per LiverTox (LiverTox: Saw palmetto) |
A tripled dose not working matters. It makes "the dose was too low" an unlikely excuse.
Label math
How much saw palmetto is in SodaPeak?
The label does not say. Saw palmetto is third of eight ingredients in a 1,200 mg blend, and blends list ingredients from most to least by weight, so it can weigh at most 400 mg per 2 capsules (FDA labeling guide ch. IV (blends)).
400 mg is the most saw palmetto could weigh, not what it does weigh. Eight ingredients share the 1,200 mg, so the real amount is almost certainly lower. At one capsule a day, the ceiling halves to 200 mg.
Even a full 320 mg would only match the dose that failed in trials. SodaPeak's bottle does not claim to help the prostate. Its only claim is "Supports healthy muscle". The full breakdown is on the saw palmetto ingredient page.
See a doctor
Which prostate symptoms need a doctor, not a supplement?
Any new urinary symptom deserves a checkup, because infection, prostatitis and prostate cancer can look like BPH. The NIDDK, part of the NIH, says to discuss any urinary symptoms with a health professional (NIDDK: Enlarged prostate (BPH)).
Cannot pass urine at all, see blood in your urine, or have pain with fever or chills.
BPH is common. The NIDDK puts it at 5-6% of men aged 40 to 64 and 29-33% of men 65 and older (NIDDK: Enlarged prostate (BPH)). Doctors have tested medicines and procedures for it. A doctor can also check your kidneys and rule out other causes.
- Getting up two or more times a night to urinate
- A weak or stop-and-start stream
- Straining, or feeling the bladder is still full
- Sudden urges or leaking
Cancer screening
Does saw palmetto change PSA or prevent prostate cancer?
No on both counts. Memorial Sloan Kettering Cancer Center (MSK) says saw palmetto did not change PSA compared with placebo, even at high doses, and has not been shown to prevent or treat prostate cancer (MSK: Saw palmetto).
NCCIH agrees that it does not appear to affect PSA (NCCIH: Saw palmetto). That is good news in one way: it should not hide a rising PSA on a screening test. Still, tell your doctor about every supplement before any prostate test.
Saw palmetto acts on the enzyme 5-alpha-reductase, which turns testosterone into a stronger hormone. MSK calls it antiandrogenic for that reason (MSK: Saw palmetto). If you have prostate cancer or take hormone therapy, ask your oncologist before using it.
Safety
What are the side effects of saw palmetto?
Side effects are usually mild and uncommon: stomach upset, dizziness and headache, per NCCIH (NCCIH: Saw palmetto). LiverTox says they occur at rates close to placebo (LiverTox: Saw palmetto).
Stomach and head
Upset stomach, dizziness and headache are the most reported (NCCIH: Saw palmetto).
Lower libido
MSK lists decreased libido, which fits its antiandrogenic action (MSK: Saw palmetto).
Blood thinners
MSK says not to take it with warfarin or other blood thinners (MSK: Saw palmetto).
Rare liver cases exist; LiverTox reports they resolved within 1 to 3 months of stopping (LiverTox: Saw palmetto). Read more about bleeding risk in our post on herbs that interact with blood thinners.
The other prostate herb
Is nettle root any better for the prostate?
The evidence is thin. One trial of 620 patients reported that 81% on nettle root improved versus 16% on placebo, but one author ran it at one center and asked for confirming trials (Safarinejad 2005: Nettle for BPH).
RxList rates nettle root as having insufficient evidence for BPH (RxList: Stinging nettle). SodaPeak lists nettle root fourth, so it holds at most 300 mg per 2 capsules. The trial's abstract does not state the dose used. See the nettle root ingredient page.
Bottom line
Should you take saw palmetto for your prostate?
Not as a stand-in for a checkup. The best NIH trials found no benefit over placebo. If urinary symptoms bother you, see a doctor, who can offer treatments that have been shown to help. SodaPeak is a dietary supplement, not a prostate treatment.
FAQ
Saw palmetto and the prostate: common questions
Is saw palmetto worth taking for nighttime urination?
Probably not. NCCIH reports that two NIH-funded trials found saw palmetto no better than placebo for enlarged prostate symptoms, which include waking at night to urinate. Getting up often at night can have several causes, so a doctor visit is the better first step.
How much saw palmetto should you take for the prostate?
Trials most often used 320 mg a day, sometimes as 160 mg twice a day, according to LiverTox. Those doses did not beat placebo in the NIH trials, and even tripling the dose did not help. No dose has a proven benefit for BPH.
Is 400 mg of saw palmetto too much?
Not by trial standards. One NIH-funded trial raised the dose to three times the usual amount, and side effects stayed mild and uncommon. In SodaPeak, 400 mg is only a ceiling from label math. The main concern is bleeding risk if you take a blood thinner.
Does saw palmetto lower PSA levels?
No. Memorial Sloan Kettering says saw palmetto did not change PSA compared with placebo, even at high doses, and NCCIH says it does not appear to affect PSA. Tell your doctor about every supplement you take before any prostate screening test.
Can saw palmetto prevent prostate cancer?
No study shows that. Memorial Sloan Kettering says saw palmetto has not been shown to prevent or treat prostate cancer. If you have prostate cancer or take hormone therapy, talk to your oncologist before using any product that contains it.
What urinary symptoms mean I should see a doctor now?
Seek care right away if you cannot urinate, see blood in your urine, or have pain with fever, says the NIDDK. Any other new urinary change also deserves a visit, since infection, prostatitis and prostate cancer can look like an enlarged prostate.
Can saw palmetto lower sex drive?
It can in some men. Memorial Sloan Kettering lists decreased libido among saw palmetto's side effects, which fits its antiandrogenic action on the enzyme 5-alpha-reductase. Stop taking it and talk to your doctor if you notice a change.
Who wrote this
Written and reviewed by
Plain-language pages built from the bottle label, the order page and linked public health sources such as NIH, FDA and CDC.
Last updated . Read our editorial standards and how we check reviews. This website is run by a U.S. stocking partner for SodaPeak, not by the manufacturer. We earn money when you buy through our order links.
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Fourth on the label at up to 300 mg, nettle root rests on one large but unconfirmed prostate trial.
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