Methylene Blue for Cognitive Function
There is no good evidence that methylene blue improves everyday cognitive function, and as a self-administered supplement it carries serious safety risks. The largest, highest-quality trials in Alzheimer's disease failed, and regulators authorize methylene blue only as a prescription antidote, not as a brain or memory supplement.
Why this grade7-layer evidence engine
This claim earns a Counter-Evidence (D) grade because the strongest data are negative. The two pivotal phase 3 trials of the methylene-blue derivative LMTM in mild-to-moderate Alzheimer's disease (PMID 27863809, n=891; PMID 29154277, n=800) missed their pre-specified primary endpoints, and the 2023 systematic review of six RCTs (PMID 38022191, n=3822) explicitly notes that the largest pivotal trials failed. The only positive signals come from small, acute, single-dose studies: a 26-person fMRI study (PMID 27351678) and a 42-person fear-extinction study (PMID 25018057), plus one perioperative intravenous trial in surgery patients (PMID 33091706, n=248). None of these support routine oral use for everyday cognition.
Independent and specialist sources reinforce the downgrade. Harvard Health reports that methylene blue, at doses similar to those in the memory research, actually reduced human brain blood flow by about 8 percent—a finding that contradicts the claimed mechanism. The Alzheimer's Association states that no supplement has been proven to benefit cognitive function or brain health, and NIH and major clinics do not address methylene blue as a cognitive aid at all.
Safety drives the safety-review status. Methylene blue is a potent MAO inhibitor: the FDA warns it can cause serious or fatal serotonin syndrome when combined with serotonergic drugs and opioids. Regulators worldwide treat it strictly as a prescription medicine—the EU (EMA/EFSA), UK NHS, and WHO authorize it only as an injectable antidote for methemoglobinemia, not as a dietary supplement. Selling or self-dosing it for cognition falls outside any approved use.
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 = 0.403
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — | C→D 因 scope.conflation_risk=true 且 L11 獨評較低 (B7-2 tier cap)
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status