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Methylene blue (methylthioninium chloride)
A century-old dye and approved drug for methemoglobinemia, used grey-market at low doses as a mitochondrial 'nootropic' and longevity aid. Small human brain-imaging trials suggest low doses can modestly aid memory/oxygen metabolism; longevity/skin evidence is preclinical. Narrow safe-dose window and real interactions (serotonin syndrome). Off-label/research use, not a supplement.
Research compound — not a dietary supplement
Methylene Blue is a research compound, not a regulated dietary supplement. It is sold for research or off-label use. The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
Methylene Blue doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 2001–2026.
Based on 63 studies · 7 meta-analyses · 45 RCTs
Confidence
High confidenceBy outcome
Low-dose methylene blue has a genuine mitochondrial mechanism and small randomized human neuroimaging studies showing modest memory/brain-metabolism effects, but there are no human longevity outcomes, the dose-response is hormetic (higher doses harm), and it carries serious interactions (serotonin syndrome, G6PD hemolysis) — so the evidence is early and the safe window narrow.
100 randomised trials
78% were about Methylene Blue in an audit of 50 of them
Every randomised or controlled trial of Methylene Blue indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Sep 2026
72 trials ongoing or recruiting · 184 completed on ClinicalTrials.gov
28 of the completed trials have posted results
Registered trials show research momentum for Methylene Blue, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Nov 2026
Methylene blue (methylthioninium chloride) is a 150-year-old synthetic dye that is also an FDA-approved drug — used intravenously to treat methemoglobinemia and as a surgical stain.
In the biohacker/longevity world it is taken orally at low doses as a mitochondrial 'nootropic.' Its mechanism is genuinely interesting: at low concentrations it acts as an alternative electron carrier in the mitochondrial electron-transport chain, accepting electrons and donating them to cytochrome c / oxygen, which can increase cellular oxygen consumption and ATP production and provides antioxidant/redox-cycling effects.
Small randomized human neuroimaging studies (functional MRI) found low-dose methylene blue increased functional MRI responses and modestly improved memory-task performance and brain oxygen metabolism.
Preclinical work suggests neuroprotection in models of cerebral ischemia and anti-aging effects on skin fibroblasts (it has been explored as a cosmetic antioxidant).
The honest picture is that the human evidence is limited to small short-term cognitive/imaging studies — there are no human longevity outcomes — and methylene blue has important caveats: it has a hormetic (biphasic) dose-response, so higher doses become pro-oxidant and harmful; it is a potent monoamine-oxidase inhibitor, creating a serious risk of serotonin syndrome with SSRIs/SNRIs and other serotonergic drugs; it can cause (harmless) blue/green urine, and is dangerous in G6PD deficiency (hemolysis).
Only USP/pharmaceutical-grade material is safe — industrial dye is contaminated. It is used off-label/as a research chemical, not a dietary supplement.
The score reflects real but small human cognitive data and intriguing mitochondrial mechanisms against a narrow safe-dose window, serious drug interactions, and no human longevity evidence.
At low doses methylene blue cycles between oxidized and reduced forms in mitochondria, shuttling electrons to cytochrome c / oxygen and supporting ATP production.
Low doses are antioxidant and pro-bioenergetic; higher doses flip to pro-oxidant and harmful — a biphasic dose-response that defines the narrow safe window.
Methylene blue is a potent MAO inhibitor — relevant to mood/cognition but the basis of the serotonin-syndrome interaction risk.
How Methylene Blue works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Avoid — serious serotonin-syndrome risk.
Avoid — hemolysis risk.
Avoid — not established as safe.
Methylene blue is a potent MAO inhibitor — combining can cause life-threatening serotonin syndrome. A widely documented, serious interaction.
Can precipitate hemolysis in G6PD-deficient individuals.
Tip: Harmless and expected; dilute to reduce staining.
Tip: More likely at higher doses; keep doses low.
Tip: Do not combine with SSRIs/SNRIs/MAOIs — potentially life-threatening.
Tip: Avoid in G6PD deficiency.
Methylene Blue has an evidence score of 3/10 — emerging evidence based on 63 indexed studies. A century-old dye and approved drug for methemoglobinemia, used grey-market at low doses as a mitochondrial 'nootropic' and longevity aid. Small human brain-imaging trials suggest low doses can modestly aid memory/oxygen metabolism; longevity/skin evidence is preclinical. Narrow safe-dose window and real interactions (serotonin syndrome). Off-label/research use, not a supplement. Representative study: PMID 26961091.
Dosing for Methylene Blue: No validated longevity dose. Nootropic use is LOW-dose (research used roughly 0.5–4 mg/kg in studies; biohacker oral use is often ~10–25 mg), USP-grade only. Higher doses become pro-oxidant and risk toxicity. Off-label/research use, not an approved regimen. (no cited human trial states a dose). Individual needs vary, so check the right dose for you with a healthcare provider.
Timing is flexible for Methylene Blue — consistent daily use matters more than the time of day. Low oral doses for cognition; stays in the low (antioxidant) part of the hormetic curve.
Methylene Blue should be used with caution — talk to a healthcare provider before taking it. Reported side effects include serotonin syndrome (with serotonergic drugs), hemolysis (G6PD deficiency), blue/green urine and oral staining. How often they occur is not established for all of them. Use caution if any of these apply to you: Use with SSRIs/SNRIs/MAOIs or other serotonergic drugs (serotonin syndrome); G6PD deficiency (hemolysis); Pregnancy / breastfeeding.
Citicoline
Probably helpsPrecursor to acetylcholine and phosphatidylcholine. One trial in 100 healthy older adults improved memory. Stroke trials are mixed.
Huperzine A
Too few graded studiesAcetylcholinesterase inhibitor from club moss, studied mainly for Alzheimer's and dementia; cognitive evidence is mixed and limited by trial quality.
Phosphatidylserine
Too few graded studiesKey brain membrane phospholipid that facilitates neurotransmitter release, memory formation, and post-exercise cortisol reduction.
Pregnenolone
Likely helpsA steroid-hormone precursor and neurosteroid being studied mainly in clinical psychiatry; human evidence is early and there is no proven benefit for cognition, mood, or anti-aging in healthy people.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 63 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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