Panax Ginseng for Immune Function
Panax ginseng shows a weak, inconsistent signal for immune function, mainly slightly fewer colds or flu and modestly stronger vaccine responses, but the supporting trials are small, old, often industry-funded, and rated low to very-low quality, so it cannot be relied on to boost immunity.
Why this grade7-layer evidence engine
The grade is weak because the positive findings come from small or dated trials while the larger syntheses are unconvincing. The most cited result is a 1996 industry-funded RCT of standardized extract G115 (PMID 8879982, n=227), which reported far fewer flu/cold cases (15 vs 42, p<0.001), higher influenza antibody titres (272 vs 171, p<0.0001), and roughly double NK-cell activity. A 2012 Korean red ginseng RCT (PMID 23255845, n=100) similarly found fewer respiratory illnesses (24.5% vs 44.9%, p=0.034), but symptom duration and severity were not significant.
Pooled evidence is far weaker. A 2011 systematic review of five RCTs (PMID 19592479, 747 adults) found only a non-significant 30% drop in catching at least one cold (RR 0.70, 95% CI 0.48-1.02), with four of five trials using manufacturer-funded COLD-fX. A 2020 meta-analysis (PMID 32951718) saw some adjunct-to-vaccination benefit but no firm conclusion, and a 2023 umbrella review (PMID 37465522) rated 81% of outcomes as very-low or low quality, with no effect on symptom duration.
Regulators and clinics reinforce caution. The FDA stopped evaluating ginseng's GRAS notice and authorizes no immune claim; the UK NHS notes herbal products are not tested like medicines and can interact with other drugs; WHO endorses ginseng only as a tonic for fatigue and convalescence, not immunity. Mayo and Harvard call the evidence preliminary. A drug-interaction flag (warfarin, blood-sugar medicines) and predominantly industry funding further limit confidence.
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 = 0.594
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 無高階證據可裁決
- tier_strict_requirement_check — | B→C 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status