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Methylene Blue

70
evidence score
nootropic
231 studies
MBmethylthioninium chlorideUrolene Blue+1 more

Methylene Blue is an FDA-approved medication (for methemoglobinemia and urinary tract infections) with a documented history as a cognitive enhancer dating to the 19th century. At low doses (0.5–4mg/kg), it acts as a mitochondrial electron carrier, improving oxidative phosphorylation efficiency and ATP production. Extensive preclinical evidence for neuroprotection, memory enhancement, and Alzheimer's/dementia-related mitochondrial dysfunction. Used experimentally for cognitive enhancement, anti-aging, and mood optimization. Hormetic dose-response: low doses are beneficial while high doses become pro-oxidant and potentially harmful. Turns urine blue — benign side effect. No significant safety concerns at low doses. Available OTC as pharmaceutical grade.

Evidence

Moderate evidence

Safety

Unknown safety profile

Clinical Status

Approved

Last Sync

Feb 19, 2026

Last Reviewed

Not reviewed yet

Physician Notes

Low dose only (10mg 3x/week). Blue urine is expected and harmless. Mild MAOI activity: avoid combining with SSRIs/SNRIs (serotonin syndrome risk).

FDA Status:FDA-approved for methemoglobinemia. Off-label for cognitive/mitochondrial support.

Monitoring

  • G6PD screen before starting (hemolytic anemia risk)
  • Medication review for serotonergic drugs

Contraindications

  • G6PD deficiency
  • Concurrent SSRI/SNRI use
  • Renal impairment
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Dosing

Typical
10 mg
0.5 mgRange80 mg
FrequencyOnce daily oral (avoid late evening due to potential stimulant effects)

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Pharmacology

Half-life~5–6 hours
OnsetAcute cognitive effects within 1–2 hours; mitochondrial effects cumulative
Duration4–8 hours per dose; blue urine for ~24 hours
Routes
oral
intravenous

Evidence Score

70
Level B — Moderate
231 studies indexed · 3 meta-analyses
Scoring Factors
Volume(24%)~47/100
Quality(24%)~47/100
Sample Size(12%)~90/100
Consistency(14%)~90/100
Replication(8%)~90/100
Recency(18%)~90/100

Scores estimated from study counts. Exact breakdown computed after research sync.

Evidence Levels
AScore ≥75 with at least 1 meta-analysis and 3+ RCTs
BScore ≥50 with at least 1 RCT or meta-analysis
CScore ≥25 — observational or animal evidence only
DScore <25 — very limited or preclinical data

Plain-English Snapshot

Methylene Blue is currently categorized as a nootropic compound.

Evidence is moderate (70/100): promising signal from 231 indexed studies, but context and population still matter.

Safety scoring is incomplete. Start conservatively and monitor carefully.

Core mechanism

Alternative mitochondrial electron carrier in complex I-IV chain; improves oxidative phosphorylation; MAO inhibitor; antioxidant at low doses; hormetic dose-response

Practical Context

Strongest current signals

  • Level C: From Theory to Therapy: Methylene Blue's Emerging Role in the Management of Septic Shock.
  • Level C: A Review of Methylene Blue's Interactions with DNA and Their Relevance for DNA-Based Sensors.
  • Level D: Clinical, imaging and blood biomarker outcomes in a Phase 3 clinical trial of tau aggregation inhibitor hydromethylthionine mesylate in mild cognitive impairment and mild to moderate dementia due to Alzheimer's disease.

Elevated caution signals

1 severe/high side effect flag

Compound Profile