Panax Ginseng for Cognitive Function
Panax ginseng is not a proven cognitive enhancer. The best evidence shows at most a small, inconsistent signal limited to memory, with no benefit for overall cognition, attention, or executive function.
Why this grade7-layer evidence engine
The grade is held to Weak (Tier C, Disputed) because the highest-quality evidence does not support a broad nootropic effect. A 2010 Cochrane systematic review (PMID 21154383) of 9 RCTs could not pool data due to heterogeneity in outcomes, dose, and duration, and concluded there is no convincing evidence of cognitive enhancement in healthy adults and no high-quality evidence in dementia. A 2024 meta-analysis (PMID 39474788, 15 RCTs, 671 participants) found a significant effect only for memory (SMD 0.19, larger at high doses, SMD 0.33), with no benefit for overall cognition, attention, or executive function.
Supportive signals come only from individual trials on isolated measures: a 2019 RCT in mild cognitive impairment (PMID 32055589) improved one memory subtest, and a 2025 RCT (PMID 40289951) improved a single CANTAB planning task, but it was industry-funded by a ginseng producer. These narrow, dose-dependent results do not amount to a reliable cognitive benefit.
Regulators and clinics reinforce the cautious grade. The FDA issues no approved cognitive claim (it ceased evaluating the relevant notice); the UK NHS notes herbal products are not tested like standard medicines and warns of interactions; and Harvard Health is negative. WHO records only a traditional tonic use, not trial-grade endorsement. Ginseng also carries interaction risks (warfarin, blood-glucose-lowering drugs), so high-dose self-supplementation for brain benefits is not advisable.
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 = 0.555
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (2 篇 > 0 negative)
- 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 1 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status