Lemon Balm for Cognitive Function
Lemon balm (Melissa officinalis) shows only weak, inconsistent evidence for improving cognitive function in healthy adults; a handful of small, dated trials hint at acute effects on attention and calmness, but memory results are mixed and no major health authority endorses it for this use.
Why this grade7-layer evidence engine
The grade is weak (Tier C) because the human evidence rests on just four small randomized trials, all published before 2010 with no recent replication. Two acute-dose crossover studies in healthy adults (PMID 12888775, n=20; PMID 12062586, n=20) produced genuinely mixed signals: a 1600 mg dose improved memory and calmness, yet lower doses slowed memory-task speed, and in the companion trial 600 mg sharpened attention accuracy while secondary and working memory actually declined and the highest dose reduced alertness.
The two remaining trials are in dementia, not healthy cognition. An Alzheimer's RCT (PMID 12810768, n=42) found a standardized extract improved cognition (ADAS-cog, p=0.01) and reduced agitation, and a severe-dementia aromatherapy trial (PMID 12143909, n=72) cut agitation by 35% versus 11% for placebo. These measure agitation and disease-specific outcomes and cannot be extrapolated to cognitive enhancement in healthy people.
Regulatory and clinical backing is thin. The US FDA lists balm leaf extract only as a GRAS flavoring agent, not an efficacy endorsement, while EFSA, the NHS, NIH ODS, Mayo and Harvard offer no substantive assessment for cognition. Cleveland Clinic notes cautiously that one small study improved mood and thinking but calls for more research. Given the small, aging, internally inconsistent dataset, a weak grade with a warning is appropriate.
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 = 0.479
- 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 — 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