Bottle of Go Wise Men's Daily Prostate capsules with saw palmetto, pygeum and plant sterols

Saw Palmetto and Beta-Sitosterol for Prostate Health: What the Evidence Shows

Saw palmetto is the best known prostate herb, but it has the weakest evidence. A 2023 Cochrane review of 27 trials found that saw palmetto on its own makes little to no difference to urinary symptoms linked to an enlarged prostate. Beta-sitosterol, a plant sterol, has more encouraging results, although the trials are older, small and short.

So if you want to support prostate and urinary health with a supplement, it makes sense to look past saw palmetto alone. This article covers what these ingredients are, what the studies found, how much was used and who should talk to a doctor first.

In brief

  • High-certainty evidence shows saw palmetto alone gives little to no benefit for urinary symptoms in men with an enlarged prostate.
  • Older trials of beta-sitosterol found better symptom scores and urine flow over up to 6 months.
  • Pygeum showed moderate benefit in small, short studies of mixed quality.
  • New or changing urinary symptoms need a doctor's visit before any supplement.

What saw palmetto and beta-sitosterol are

Saw palmetto (Serenoa repens) is a small palm that grows in the southeastern United States. Extracts of its berries have been used for decades in Europe for urinary symptoms in older men. The idea is that compounds in the berry may affect how the prostate responds to hormones.

Beta-sitosterol is a plant sterol, a fat-like compound with a structure similar to cholesterol. It is found in nuts, seeds, soybeans and vegetable oils. Supplements usually contain a mix of sterols rather than beta-sitosterol alone. Pygeum comes from the bark of the African cherry tree (Pygeum africanum) and is often paired with the other two.

These ingredients are usually taken for symptoms from benign prostatic hyperplasia (BPH), the non-cancerous growth of the prostate that becomes common with age. A larger prostate can press on the urethra, which can mean a weaker stream, more trips to the bathroom and waking at night to urinate.

What the evidence shows

Saw palmetto has been tested more than any other prostate herb, and the results are disappointing. The 2023 Cochrane review pooled 27 randomized trials with 4,656 men (Franco et al., Cochrane Database of Systematic Reviews 2023). In the trials at low risk of bias, saw palmetto alone made little to no difference to symptom scores or quality of life at 3 to 6 months or at 12 to 17 months. The reviewers rated this evidence as high certainty. For saw palmetto combined with other plant ingredients, the evidence was low certainty and they could not draw firm conclusions.

A larger dose doesn't seem to help. In the US CAMUS trial, 369 men took saw palmetto extract at 320 mg a day, then 640 mg, then 960 mg, over 72 weeks. Symptoms improved about as much on placebo as on saw palmetto (Barry et al., JAMA 2011).

Beta-sitosterol looks better, with caveats. A Cochrane review of 4 trials in 519 men found that beta-sitosterol improved symptom scores by about 4.9 points on the International Prostate Symptom Score and raised peak urine flow by about 3.9 mL per second compared with placebo (Wilt et al., Cochrane Database of Systematic Reviews 2000). It did not shrink the prostate. The trials lasted 4 to 26 weeks, and the authors said long-term effects and safety were unknown. The largest of them gave 200 men 20 mg of beta-sitosterol three times a day for 6 months and found better symptom scores and urine flow than placebo (Berges et al., Lancet 1995).

Pygeum sits somewhere in between. A Cochrane review of 18 small trials in 1,562 men found that men taking pygeum were about twice as likely to report overall improvement as men on placebo, with less nighttime urination and better flow (Wilt et al., Cochrane Database of Systematic Reviews 2002). The studies averaged about two months, used different doses and preparations, and often did not use standard symptom scales.

Put plainly: the strongest evidence is negative for saw palmetto alone, and the more positive evidence for beta-sitosterol and pygeum is old and thin. None of these herbs has been shown to reduce prostate size.

Dose, forms and how to take them

Most saw palmetto trials used 320 mg a day of a fat-soluble berry extract. Whole berry powder is a different form and has been studied far less. In the main beta-sitosterol trial, men took 60 mg a day, split into three doses. Pygeum trials used a range of doses, so there is no well-established amount.

Because sterols and saw palmetto extracts are fat-soluble, taking them with a meal is a sensible habit. Give any supplement a fair trial of a few months, since most studies measured results at 3 to 6 months, and keep track of how often you get up at night so you have something concrete to compare.

Formulas for men often add zinc and selenium, both needed in small amounts for normal body function. If you want the background on zinc, our guide to vitamins and zinc covers it. More isn't better with minerals: the daily value for zinc is 11 mg, and long-term high intake can lower copper levels.

Who should be careful

Urinary symptoms can come from many causes, including an infection, diabetes, medication side effects and, less often, prostate cancer. See a doctor before trying a supplement, and again if symptoms get worse, you see blood in your urine or you can't urinate.

NCCIH describes saw palmetto as generally well tolerated in studies lasting up to 3 years, with occasional digestive upset, dizziness or headache. It does not appear to affect PSA readings (NCCIH, Saw Palmetto). If you take finasteride, dutasteride, tamsulosin or another prostate drug, ask your prescriber before adding an herbal product.

Multi-herb formulas need a closer look. Goldenseal, for example, can change how the body handles some medicines. NCCIH notes that it lowered metformin levels by about 25 percent in healthy adults, and that people who are pregnant or breastfeeding should not use it (NCCIH, Goldenseal). Read the full ingredient list, including any blend, and show it to your pharmacist if you take regular medication. People with a soy allergy should check whether the plant sterols come from soy.

Where Go Wise Men's Daily Prostate fits

Go Wise Men's Daily Prostate is a two-capsule daily serving with saw palmetto fruit 200 mg, pygeum bark powder 100 mg and a soy plant sterol complex 50 mg, alongside zinc 12 mg, selenium 55 mcg, vitamin B6 2 mg, vitamin E 13 mg and copper 4 mg. It also includes nettle root, green tea, tomato, broccoli, mushrooms and other botanicals, plus a 176 mg proprietary blend that contains goldenseal and uva ursi. It comes in vegetable capsules, contains soy, is made in the USA. Our article on third-party tested supplements explains what that testing covers. Every batch is third-party tested by Eurofins for heavy metals and microbial contamination, and it is made in a GMP-certified facility.

Frequently asked questions

Does saw palmetto change PSA test results?

According to NCCIH, saw palmetto does not appear to affect PSA readings, even at higher doses. Still, tell your doctor about every supplement you take before a PSA test.

Is beta-sitosterol the same as plant sterols?

Beta-sitosterol is one plant sterol. Supplements labeled beta-sitosterol or plant sterols usually contain a mix of several sterols, and the trial by Berges and colleagues used a phytosterol mixture.

How long should I try a prostate supplement before judging it?

The trials discussed here ran from about one month to 72 weeks, and most measured results after 3 to 6 months. If your symptoms change quickly or get worse, see a doctor rather than waiting.

Can I take a prostate supplement with finasteride or tamsulosin?

Ask your prescriber first. There is little research on combining these herbs with prescription prostate medicines, and your doctor will want to know about anything that could affect your symptoms or test results.

References

This article is for general information and isn't medical advice. Talk to your healthcare provider before starting a supplement, especially if you are pregnant, nursing or taking other medication.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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