Quercetin for Hypertension
Quercetin appears to produce a small but consistent reduction in blood pressure, on the order of 2-3 mmHg, mainly at doses of 500 mg/day or higher and in people who are already pre-hypertensive or hypertensive. It is not a substitute for proven first-line measures, and its long-term effect on actual cardiovascular events is unknown.
Why this grade7-layer evidence engine
Four independent meta-analyses pooling roughly 590 to 900 participants point the same direction. The two largest (PMID 31940027, n=896 across 17 trials; PMID 35948195, n=841) found systolic reductions of about 2.4 to 3.1 mmHg, an earlier review (PMID 27405810, n=587) reported -3.04 mmHg systolic and -2.63 mmHg diastolic, and a metabolic-syndrome analysis (PMID 31092175) still showed a significant -1.69 mmHg systolic. This agreement across separate datasets is what lifts the claim above weak/exploratory evidence.
The grade stays at preliminary rather than higher because the effect is small and its real-world importance is unproven. Benefit clusters at doses of 500 mg/day and above, so lower-dose products may do little; diastolic results are inconsistent and non-significant in the metabolic-syndrome group (PMID 31092175); the trials are heterogeneous; and funding for most reviews is undisclosed, so industry bias cannot be ruled out. No trial has tested whether quercetin prevents strokes or heart attacks.
Authorities are cautious to unsupportive. EU EFSA rejected quercetin's cardiovascular health claims for lack of an established cause-and-effect relationship; the US FDA treats it as a food ingredient (GRAS) but has warned companies against disease claims; and the WHO/IARC statement only addresses carcinogenicity (Group 3), not blood pressure. Mayo, Cleveland Clinic and Harvard do not endorse it as a supplement for hypertension, and no major guideline recommends it over diet, exercise, or medication.
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 = 0.61
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (4 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status