Methylene Blue
NootropicsPreclinicalAlso known as: MB, MB Vape, Methylene Blue Vape
Methylene blue (methylthioninium chloride) is a phenothiazine dye with a 150-year pharmacology record. It was the first fully synthetic drug ever used in medicine (Ehrlich, 1891 for malaria) and remains on the WHO Model List of Essential Medicines as the first-line treatment for acquired methemoglobinemia.
Overview
At A Glance
Methylene blue (MB) has a multi-target redox mechanism that explains why it appears in such disparate indications as malaria, methemoglobinemia, septic shock, vasoplegia, Alzheimer's (TRx0237), and cognitive enhancement:…
Mechanism of Action
Methylene blue (MB) has a multi-target redox mechanism that explains why it appears in such disparate indications as malaria, methemoglobinemia, septic shock, vasoplegia, Alzheimer's (TRx0237), and cognitive enhancement:
1. Alternative mitochondrial electron carrier (primary nootropic mechanism)
At low micromolar concentrations, MB accepts electrons from NADH and donates them directly to cytochrome c, bypassing Complex I and Complex III of the electron transport chain (Atamna et al., 2008, FASEB J). This matters because Complex I is the most common site of age-related mitochondrial failure and the target of rotenone-induced Parkinson's models. By providing an electron shunt, MB:
- Increases cytochrome c oxidase (Complex IV) activity by 30-70% in neuronal tissue
- Raises cellular oxygen consumption without increasing reactive oxygen species
- Extends lifespan of cultured human fibroblasts by ~20% and delays senescence markers
- Rescues mitochondrial function in neurons exposed to amyloid-beta, rotenone, and MPP+
Rojas, Bruchey & Gonzalez-Lima (2012) showed that a single 4 mg/kg oral dose in rats produced measurable cytochrome oxidase activation in frontal cortex and hippocampus 24 hours after administration, with improved extinction of Pavlovian fear conditioning.
2. Nitric oxide synthase (NOS) and soluble guanylate cyclase (sGC) inhibition
MB inhibits both NOS isoforms and sGC, which is why it is deployed in vasoplegic shock after cardiac bypass — it raises mean arterial pressure in catecholamine-resistant hypotension by blocking the NO/cGMP pathway that drives pathologic vasodilation. In the brain, this same mechanism explains why MB is contraindicated with serotonergic drugs: reduced NO/cGMP activity combined with MB's potent MAO-A inhibition (Ki ~ 5 μM) can precipitate serotonin syndrome.
3. Tau aggregation inhibition (the TauRx story)
Methylene blue was the lead compound that became leuco-methylthioninium bis(hydromethanesulfonate) / TRx0237 / hydromethylthionine mesylate, now in Phase 3 Alzheimer's trials by TauRx Therapeutics. MB inhibits tau-tau binding in the paired helical filaments that drive Alzheimer's pathology (Wischik et al., 1996). The LUCIDITY Phase 3 trial (Wilcock et al., 2023) showed slower cognitive decline at 16 mg/day in mild-moderate Alzheimer's.
4. Methemoglobin reductase
At 1-2 mg/kg IV, MB donates electrons via NADPH-methemoglobin reductase to reduce Fe³⁺ methemoglobin back to Fe²⁺ hemoglobin, restoring oxygen-carrying capacity. This is the basis for its FDA-approved use in acquired methemoglobinemia.
5. MAO-A and MAO-B inhibition
MB is a reversible, potent MAO-A inhibitor and weaker MAO-B inhibitor, which creates real drug-interaction hazards (SSRIs, SNRIs, tramadol, MDMA, St. John's Wort, Sinemet). Multiple deaths from serotonin syndrome in perioperative methylene blue administration have been reported to the FDA (FDA Drug Safety Communication, 2011).
6. Photodynamic effects
Under red/near-infrared light (660-810 nm), MB generates singlet oxygen in a targeted way, which is the basis for photodynamic therapy applications. Many biohackers pair oral MB with red-light panels, though the systemic evidence for the combination is thin.
The practical takeaway: MB is not a "stimulant" or "cognitive enhancer" in the caffeine sense. It is a mitochondrial remediation agent whose nootropic effect is secondary to restored bioenergetics in stressed or aging neurons — and its dose-response is sharply inverted-U. More is not better.
Overview
Methylene blue (methylthioninium chloride) is a phenothiazine dye with a 150-year pharmacology record. It was the first fully synthetic drug ever used in medicine (Ehrlich, 1891 for malaria) and remains on the WHO Model List of Essential Medicines as the first-line treatment for acquired methemoglobinemia. In the last decade it has re-emerged in biohacking circles because low doses (~0.5 to 4 mg/kg) act as an alternative mitochondrial electron carrier, bypassing damage at Complex I/III of the respiratory chain and boosting cytochrome c oxidase activity (Atamna et al., 2008).
The molecule has an auto-oxidizing redox cycle: reduced leucomethylene blue donates electrons to cytochrome c, then the oxidized form accepts electrons from NADH, effectively forming a "shunt" around dysfunctional mitochondrial complexes. This is why low-dose MB improves cerebral oxygen consumption and memory performance in humans, while high doses paradoxically inhibit the same system — the dose-response curve is hormetic and inverted-U, one of the most-cited nootropic examples in the field.
There are two entirely different use cases for methylene blue, and collapsing them is the most common cause of harm:
- Medical methemoglobinemia rescue (1-2 mg/kg IV): Life-saving antidote delivered by clinicians for nitrate/nitrite/benzocaine/dapsone poisoning. Non-negotiable pharmaceutical-grade material, hospital setting.
- Nootropic/mitochondrial microdosing (0.5-4 mg oral per day): Off-label self-experimentation. Requires USP pharmaceutical-grade only — not the industrial textile dye sold on aquarium or lab-chemistry sites, which contains arsenic, cadmium, mercury, and other heavy metals above safe intake thresholds.
If a vendor cannot produce a third-party Certificate of Analysis showing USP purity (>99%) with heavy-metal testing, it is not safe for ingestion at any dose. See our Vendor COA Guide and Methylene Blue Complete Guide for sourcing protocol.
Potential Research Fields
Chemical Information
IUPAC Name
3,7-bis(dimethylamino)phenothiazin-5-ium chloride
CAS Number
61-73-4
Molecular Formula
C16H18ClN3S
Molecular Mass
319.85 g/mol
Dosing & Protocols
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Interactions
Interaction Matrix
Contraindications
Absolute contraindications (do not use at therapeutic doses)
- G6PD deficiency — causes acute hemolytic anemia. Test before use.
- Pregnancy — crosses placenta; causes fetal hemolysis and methemoglobinemia.
- Current SSRI/SNRI/serotonergic drug therapy — serotonin syndrome risk. Full washout required.
- Infants <4 months — limited hepatic metabolism; risk of methemoglobinemia.
- Severe renal impairment (eGFR <30) — accumulation risk; avoid or dose-reduce dramatically.
Relative contraindications (clinician-guided only)
- Hepatic impairment (Child-Pugh B or higher)
- Known methemoglobinemia-inducing drug therapy (dapsone, benzocaine, high-dose nitrates)
- Hemolytic anemia of any etiology
- History of serotonin syndrome
- Phenylketonuria (some formulations contain phenylalanine)
- Active photosensitivity disorders (porphyria, lupus with photosensitivity)
Surgery and procedural considerations
- Pulse oximetry interference: MB falsely depresses SpO₂ readings by ~5% for 30-60 min after administration. Inform anesthesia team if you have dosed recently.
- Co-oximetry is unaffected — use for true oxygenation assessment.
- Serotonergic anesthetics: Many perioperative agents (fentanyl, tramadol, dexmedetomidine at very high doses) have serotonergic activity. Disclose MB use to anesthesia at pre-op.
What to disclose to any clinician
- Dose, frequency, brand/vendor
- Duration of use
- Most recent dose (especially within 72 hours)
- All concurrent supplements (many users forget that 5-HTP, St. John's Wort, tryptophan count as serotonergic)
Research Disclaimer
This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds.
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| Vendor | Product | Form | Qty | Price | $/mg | Coupon | |
|---|---|---|---|---|---|---|---|
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Methylene Blue 1% 60ml | oral | 60ml● Out of Stock | $24.00BEST | $0.040 | — | Sign in for stock alert |
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Methylene Blue 1% 30mL | vial | 30mL bottle● In Stock | $19.99 | — |
Tracking since Apr 6, 2026 · 3 data points
Price History
3 data pointsVendors Selling Methylene Blue
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Protocols, calculator & safety for Methylene Blue
Research Score
30273 PubMed studies
Quality Indicators
Data Completeness
100%Research Credibility
Well-researched compound
Quick Facts
Molecular Weight
319.85 g/mol
CAS Number
61-73-4
Trial Phase
Preclinical
Research Disclaimer
This information is for educational and research purposes only. Not intended as medical advice. Consult a healthcare professional before use.
Frequently Asked Questions
Is methylene blue safe for daily use?
For healthy adults with confirmed G6PD sufficiency, no serotonergic drug use, and pharmaceutical-grade USP material, low-dose (5-15 mg/day) methylene blue has been self-administered for years in biohacking communities without documented serious adverse events. That said, no controlled human trial has run longer than 12 months at nootropic doses, so long-term safety is inferred rather than proven. The TauRx LUCIDITY trial at 16 mg/day ran 12 months with an acceptable safety profile in older Alzheimer''s patients. Daily use at low doses is likely safe for most healthy adults; 5-days-on, 2-days-off cycling is a reasonable conservative pattern.
What is the optimal dose for cognitive enhancement?
The dose-response curve for methylene blue is strongly inverted-U. In rodent studies, 1-4 mg/kg improves memory while doses above 5 mg/kg impair it. Human-equivalent dosing (surface-area-corrected) puts the cognitive window at roughly 0.1-0.3 mg/kg, which is 7-22 mg for a 75 kg adult. Most experienced users settle at 5-15 mg/day taken in the morning. Escalating beyond 20 mg in search of ''more benefit'' typically reduces cognitive performance — a paradox well documented in the Gonzalez-Lima lab animal work and consistent with user reports.
Can I take methylene blue with my SSRI or antidepressant?
Absolutely not without a full washout. Methylene blue is a potent, reversible MAO-A inhibitor at standard oral doses. Combining it with any SSRI, SNRI, tramadol, triptan, St. John''s Wort, 5-HTP, L-tryptophan, dextromethorphan, or MDMA can cause serotonin syndrome — a life-threatening condition with documented fatalities in the FDA perioperative literature. If you take a serotonergic drug, wash out for at least 2 weeks (5 half-lives) with physician oversight before ever using MB. This is the single most important safety item on methylene blue.
How do I know if my methylene blue is pharmaceutical-grade?
Require a third-party Certificate of Analysis showing >99% purity and heavy-metal testing under USP standards (arsenic <1 ppm, cadmium <1 ppm, mercury <1 ppm, lead <10 ppm). Industrial-grade MB (textile dye, aquarium fish treatment, ACS laboratory reagent) routinely exceeds these limits and contains contaminants that are dangerous to ingest even at low doses. If a vendor cannot produce a current COA, treat the product as industrial-grade and do not consume. See our COA Verification Guide for a walkthrough on validating a certificate.
Why does methylene blue turn my urine blue-green?
This is normal and expected. Methylene blue is a deep-blue dye that is renally excreted largely unchanged, so urine takes on a distinctive blue-green color within hours of dosing and clears 24-48 hours after the last dose. It is cosmetic, not a sign of toxicity. Stools may turn dark green for the same reason. Sweat, saliva, and tears can also take on a faint blue tinge at higher doses. If you notice dark or red-brown urine, that is a different finding — consistent with hemolysis — and requires immediate evaluation.
Does methylene blue interact with coffee or caffeine?
No clinically significant interaction. Many users pair 5-10 mg MB with morning coffee, and the combination is generally well-tolerated. Theoretical concerns about CYP1A2 (which metabolizes caffeine) and MB''s weak CYP inhibition have not translated into reported problems. If you are sensitive to either compound, separate by 2-3 hours. Black coffee is also a good dilution vehicle for MB to reduce tooth staining.
Can methylene blue reverse brain fog from COVID-19 or chronic fatigue?
There are individual case reports and small case series suggesting benefit, but no controlled clinical trial evidence. The theoretical basis is strong — long-COVID and ME/CFS both involve mitochondrial dysfunction, and MB bypasses damaged mitochondrial complexes. A short trial of 5-10 mg/day for 4-6 weeks with cognitive tracking is a reasonable experiment in consultation with a clinician, but treat claims of guaranteed reversal with skepticism until proper RCTs are run.
What''s the difference between methylene blue and methylthioninium / TRx0237?
Methylene blue (methylthioninium chloride) is the parent compound. TRx0237 (hydromethylthionine mesylate, LMTM) is a stabilized leuco form of MB developed by TauRx Therapeutics. It has better oral bioavailability and a cleaner GI tolerability profile, and it is the specific investigational drug in the Phase 3 LUCIDITY Alzheimer''s trial (Wilcock 2023). Pharmacokinetically they are similar; practically, TRx0237 is only available through clinical trials, whereas USP MB is available over the counter for cognitive use.
Should I pair methylene blue with red light therapy?
Many users do, based on the photochemistry of MB under red/near-infrared light. MB absorbs 660 nm red light strongly and 810 nm NIR moderately, generating singlet oxygen that has been shown in vitro to have neuroprotective and antimicrobial effects. Human controlled data for the combination on cognition is limited. If you pair them, dose MB first, wait 45-60 minutes for absorption, then run 10-20 min red-light exposure. The combination is anecdotally well-tolerated; start conservatively and watch for headache, which is the most common complaint.
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