Beta-sitosterol
A plant sterol with some of the better trial results in the category: improved symptom scores and flow in several randomized trials, though none measured prostate size changes and the trials are old.
- Dose used in trials
- 60 to 130 mg/day of beta-sitosterol, split into two or three doses
- Time to effect
- 4 to 8 weeks
What the evidence says
A Cochrane review of four trials (519 men) found beta-sitosterol improved symptom scores and peak flow versus placebo, with no change in prostate volume. Trials ran 4 to 26 weeks. No large modern trial has repeated the result, so the evidence is moderate but dated.
What it is
Beta-sitosterol is the most common plant sterol, found in nuts, seeds and vegetable oils. It is the same compound that gives pumpkin seed oil and saw palmetto part of their activity, which is why some 'prostate complexes' are mostly beta-sitosterol relabelled.
What the trials found
The best-known trial (Berges 1995, 200 men, 60 mg a day for six months) showed a drop in symptom score of about 7 points against 2 for placebo, and better flow. A follow-up found the benefit persisted at 18 months in men who kept taking it.
The weakness is age: most trials are from the 1990s and none used modern outcome measures or large samples. Nothing since has contradicted them, but nothing has confirmed them either.
Side effects
- Mild gastrointestinal effects (gas, constipation) in a small minority
- Reduces absorption of fat-soluble vitamins slightly at high doses
Interactions
- Adds to the cholesterol-lowering effect of statins and ezetimibe, which is usually fine but worth telling your doctor
- No known interaction with prostate medications
NOW Beta-Sitosterol Plant Sterols (CardioAid-S), 90 softgels
Look for a product that states beta-sitosterol in milligrams, not 'plant sterols' as a vague total.
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Frequently asked questions
- Is beta-sitosterol better than saw palmetto?
- The trial results are cleaner for beta-sitosterol, but the trials are smaller and older. Many men take both; there is no evidence either way on combining them.
Other prostate ingredients
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