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Beta-Sitosterol
Plant sterol that improved BPH urinary symptoms and urine flow in placebo-controlled trials at 60 to 130 mg a day, without shrinking the prostate. Gram doses of plant sterols for cholesterol are a separate entry.
What the evidence says
Beta-Sitosterol doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1976–2026 with a typical study size of 109 participants.
Based on 71 studies · 9 meta-analyses · 52 RCTs · 11,264 total participants
Confidence
High confidenceBy outcome
Moderate 5.0, scored on the BPH evidence alone now that the LDL evidence is scored on the Plant Sterols & Stanols entry (owner ruling, 12 October 2026). A Cochrane review of four double-blind placebo-controlled trials (519 men) found better urinary symptom scores (IPSS 4.9 points lower) and urine flow, and the two largest six-month trials (200 and 177 men) agree. It is held at the bottom of Moderate because all four trials are from the 1990s and lasted at most 26 weeks, the preparations were not standardised, prostate size did not shrink, long-term effectiveness and prevention of complications are unknown, and the 18-month data come from an open follow-up of 59% of one trial's men.
43 randomised trials
every one checked individually
Every randomised or controlled trial of Beta-Sitosterol indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Jul 2026
9 trials ongoing or recruiting · 92 completed on ClinicalTrials.gov
7 of the completed trials have posted results
Registered trials show research momentum for Beta-Sitosterol, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Oct 2026
Under EU law (Reg. 1924/2006), EFSA reviews whether a specific health claim for Beta-Sitosterol meets the evidence standard. These are independent regulatory decisions on claims — not studies, and never counted toward the evidence score above.
Not authorised by EFSA
“Beta sitosterol Helps maintain normal kidney and prostate function”
“Not authorised” means the specific claim wording did not meet the EU’s evidence standard — often a matter of dossier or phrasing, not proof of no effect. EFSA judges marketing claims and is kept separate from our study-based evidence score.
Source: EU Register of nutrition and health claims (European Commission / EFSA) · register snapshot Feb 2013
Beta-sitosterol is one of the most common plant sterols, found in foods like nuts, seeds and vegetables. As a supplement it is used for the urinary symptoms of benign prostatic hyperplasia (BPH).
In two six-month placebo-controlled trials, 60 mg a day (200 men) and 130 mg a day (177 men) of phytosterol extracts with beta-sitosterol as the main component improved symptom scores and urine flow, and a systematic review of four trials (519 men) found the same, although none showed a smaller prostate and the trials were short and used non-standardised preparations.
Plant sterols also lower LDL cholesterol, but only at gram doses: that use, at 2 to 3 g a day of plant sterols or stanols, is covered by the separate Plant Sterols & Stanols entry, and the 60 to 130 mg used for BPH is far below it.
May reduce DHT in prostate tissue
Plant sterols block cholesterol absorption in the gut, but LDL falls only at gram doses. The 60 to 130 mg a day used for BPH is far below the 1.5 to 3 g that lowers LDL, which is covered by the Plant Sterols & Stanols entry.
How Beta-Sitosterol works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Well-supported use; get proper diagnosis first
Similar mechanisms; may be redundant A grade for this interaction is held for clinical review and has not been validated, so no severity is given. The precaution still applies: ask a pharmacist about the exact supplement and medicine. Do not stop or change prescribed medicines based on this notice.
Tip: Take with food
Beta-Sitosterol has an evidence score of 5/10 — moderate evidence based on 71 indexed studies, including 7 meta-analyses. Plant sterol that improved BPH urinary symptoms and urine flow in placebo-controlled trials at 60 to 130 mg a day, without shrinking the prostate. Gram doses of plant sterols for cholesterol are a separate entry. Representative study: PMID 39889171.
The commonly studied dose of Beta-Sitosterol is 60 to 130 mg a day for BPH urinary symptoms, the doses of the two six-month placebo-controlled trials: 20 mg three times a day, and 130 mg of free beta-sitosterol once a day. Both used phytosterol extracts with beta-sitosterol as the main component, so check the label for the beta-sitosterol content. For lowering cholesterol, gram doses of plant sterols or stanols are a different product: see the Plant Sterols & Stanols entry. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Timing is flexible for Beta-Sitosterol — consistent daily use matters more than the time of day. The BPH trials gave it either in three daily doses (20 mg three times a day) or once a day (130 mg), and no trial compared timings.
Beta-Sitosterol is generally well-tolerated and considered safe for most healthy adults at recommended doses. Reported side effects are uncommon and include GI discomfort. Use caution if any of these apply to you: Sitosterolemia (rare genetic condition).
Soy Isoflavones
Likely helpsPlant compounds with weak estrogenic effects that support menopausal symptoms, bone health, and cardiovascular function.
DHEA
Probably helpsAdrenal hormone precursor that declines with age. In postmenopausal women with normal adrenal function, trials found no effect on sexual symptoms or metabolic markers.
CoQ10
Likely helpsA lipid-soluble antioxidant central to mitochondrial energy production, with the strongest trial support for fertility/IVF outcomes and heart failure.
Berberine
Likely helpsActivates AMPK to regulate blood sugar, improve insulin sensitivity, and support lipid metabolism. Its only head-to-head trial with metformin cited here was a 36-person pilot, which does not show it can replace metformin.
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Reviewed by Dr. Baher Al Hakim · Last reviewed October 2026 · evidence from 71 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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