Saw Palmetto for Benign Prostatic Hyperplasia
For benign prostatic hyperplasia (BPH), high-quality trials show standard saw palmetto supplements work no better than placebo for urinary symptoms or flow. The lone positive signal comes from one patented, industry-funded extract that does not represent the products sold to consumers.
Why this grade7-layer evidence engine
This earns a counter-evidence (D) grade because the strongest, most rigorous studies are decisively negative. The government-funded STEP trial (PMID 16467543, n=225) found saw palmetto no better than placebo on the AUA Symptom Index, urinary flow, prostate size, PSA, or quality of life, and the CAMUS trial (PMID 21954478, n=369) confirmed no benefit even when the dose was escalated to triple the usual amount (960 mg/day), refuting the idea that typical doses are simply too low.
A 2012 Cochrane review pooling 32 randomized trials in 5,666 men (PMID 22551330) reached the same conclusion: no improvement in lower urinary tract symptoms or maximum flow versus placebo. The only favorable result is a meta-analysis of the patented Permixon hexanic extract (PMID 28723522), but it is industry-funded (Pierre Fabre) and applies solely to that specific extract, not to the generic saw palmetto capsules most people buy.
Health authorities align with this verdict. The UK NHS states saw palmetto is no more effective than placebo for BPH and that no product has been conclusively shown to work, and the NIH's NCCIH says it is probably not helpful for prostate-related urinary symptoms. The American Urological Association's guideline does not recommend it. Because urinary symptoms can also signal prostate cancer, self-treating with saw palmetto risks delaying proper diagnosis.
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditable▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.311
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高階證據未達主導 (1 positive vs 1 negative)，由 raw_score 決定
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status