What it is
Methylene Blue, also called methylthioninium chloride, is a synthetic chemical compound — not a peptide, not a vitamin. It is an old and very well-established medicine: the World Health Organization lists it on its List of Essential Medicines, meaning it considers it a vital medication for a basic health system.
It is credited with a broad variety of benefits: anti-ageing effects, cognitive support, mood regulation, fighting infectious disease and cancer, and reducing death and illness. It is an antioxidant — it neutralises free radicals, unstable molecules that damage cells — as well as anti-inflammatory, and it has effects on metabolism.
The part that matters most for how it feels day to day is what it does inside mitochondria, the tiny structures in your cells that turn food into usable energy. Mitochondria make energy by passing electrons down a chain of proteins. When part of that chain is faulty, the whole process backs up. Methylene Blue can carry electrons itself, effectively bridging the gap — which is why it improves mitochondrial function and why the cognitive effects are attributed to it.
This page covers the 25 mg oral pill.
Read the interactions section before you take this. Methylene Blue blocks an enzyme called MAO-A (monoamine oxidase A), which is one of the ways your body breaks down serotonin. Combining it with antidepressants or anything else that raises serotonin can cause serotonin syndrome, which can be life-threatening.
Methylene Blue (methylthioninium chloride) is a phenothiazinium redox dye, on the WHO List of Essential Medicines, with an unusually broad pharmacology spanning bioenergetics, redox biology, nitric oxide signalling, antimicrobial activity, and haematology.
Its core mechanism is as an alternative electron carrier: it accepts electrons from NADH and donates them to cytochrome c, bypassing complexes I and III of the mitochondrial respiratory chain. That confers benefit precisely where complex deficiency limits flux, and it is the basis of its mitochondrial and neurodegenerative claims. It is lipophilic, crosses the blood-brain barrier efficiently, and reaches high brain concentrations.
Secondary mechanisms: direct antioxidant activity, nitric-oxide modulation with cardiovascular consequences, neuroprotection, cognitive enhancement via increased cerebral blood flow, and antimicrobial disruption of bacterial function.
The pharmacology that dominates safety is its MAO-A inhibition. Methylene Blue is a potent reversible MAO-A inhibitor, and the FDA-level warning that follows — serotonin syndrome on co-administration with serotonergic agents — is the single most important item on this page. It is also metabolised by CYP1A2, and it is a redox stressor to erythrocytes lacking NADPH-dependent protection, hence the G6PD deficiency contraindication.
The oral pill here is 25 mg, one per day.
What it does
Methylene Blue works through six mechanisms.
Mitochondrial function. It improves how mitochondria work, promotes cellular energy production, and this is thought to offer therapeutic benefit for conditions where brain cells break down.
Antioxidant activity. It neutralises free radicals, the harmful molecules that damage cells and contribute to ageing and disease. Clearing them protects cells from oxidative stress.
Nitric oxide regulation. Nitric oxide is a molecule involved in many body processes, including widening blood vessels. By adjusting nitric oxide levels, Methylene Blue affects heart health and blood flow.
Neuroprotection. It helps keep nerve cells alive and working, reducing the risk of diseases where nerve cells degenerate.
Cognitive enhancement. It increases blood flow to the brain, and improves memory and attention.
Antimicrobial action. It can disrupt how bacteria and other microbes work, making it a possible addition to other treatments for infection.
The pharmacology falls under six headings.
Mitochondrial function: improved respiratory chain efficiency, increased cellular energy production, and therapeutic potential in neurodegenerative conditions — mechanistically the electron-shuttle bypass of deficient complexes.
Antioxidant activity: free-radical neutralisation and protection from oxidative stress. Worth holding alongside the hemolysis risk, since methylene blue is redox-active in both directions and is a pro-oxidant in erythrocytes lacking NADPH regeneration.
Nitric oxide regulation: modulation of NO levels with consequences for vasodilation, cardiovascular health, and blood-flow regulation. This is the mechanism behind its clinical use in vasoplegic syndrome and septic shock, both of which appear in the benefits list.
Neuroprotection: preservation of neuronal viability and function, reducing neurodegenerative risk.
Cognitive enhancement: increased cerebral blood flow, improved memory and attention. Combined with efficient blood-brain barrier penetration and high observed brain concentration, this is the nootropic case.
Antimicrobial action: disruption of bacterial and microbial function, positioned as an adjunct to conventional antimicrobial therapy.
Benefits
Evidence grades: what the labels mean
- Human trials Supported by randomised or placebo-controlled human trials.
- Limited human data Some human evidence, such as pilot studies, case reports or observational data, but no controlled trials.
- Animal or lab only Shown in animal or cell studies only; not yet tested in people.
- Anecdotal No published studies; based on user reports or theory.
Each grade reflects the strongest published support for that specific claim, not for the compound as a whole.
- Helps electrons move through the energy-producing chain in mitochondria, bypassing certain faults in that chain and reducing oxidative stress. That improves mitochondrial function, boosts cellular energy production, and may help in conditions where brain cells break down.Animal or lab only
- Acts as an antioxidant, neutralising harmful free radicals that damage cells and contribute to ageing and disease, protecting cells from oxidative stress.Animal or lab only
- Adjusts nitric oxide levels, which has positive implications for heart health and blood flow.Animal or lab only
- Protects nerve cells by keeping them alive and functioning, potentially reducing the risk of diseases where nerve cells degenerate.Animal or lab only
- Improves thinking by increasing blood flow to the brain and improving memory and attention.Limited human data
- Its antimicrobial properties disrupt how bacteria and other microbes work, making it an effective addition to standard antimicrobial treatment.Limited human data
- It dissolves in fat, so it crosses the barrier protecting the brain efficiently; high concentrations are seen in the brain after a dose.Animal or lab only
- Counteracts cells ageing before their time.Animal or lab only
- Reduces markers of ageing in body tissues.Animal or lab only
- Reduces ABAD (amyloid-binding alcohol dehydrogenase), which damages brain cells, while raising levels of estradiol.Animal or lab only
- Helps ease symptoms of hepatic encephalopathy — loss of brain function caused by toxins building up in the blood because of liver damage.Animal or lab only
- Works with macroautophagy — the cell's process for breaking down and recycling its own worn-out parts — to stop brain cells dying when they are short of nutrients.Animal or lab only
- Is an antidote for cyanide or carbon monoxide poisoning.Animal or lab only
- Helps treat urinary tract infections.Limited human data
- Reduces the death rate in people with low blood pressure after heart surgery, a condition called postoperative vasoplegia or vasoplegic syndrome.Human trials
- Used in the management of septic shock — the dangerous drop in blood pressure caused by severe infection.Human trials
- Drastically reduces harm and deaths in children with shock that has not responded to fluid and catecholamine therapy.Limited human data
- Increases mean arterial pressure — the average pressure in the arteries — which in septic shock reduces the need for other medications, shortens hospital stays, and improves heart function and oxygen levels.Human trials
- Can treat psychotic and mood disorders, improve memory in fear-extinction training, and shows promise in short- and long-term treatment of bipolar disorder; it offers antidepressant and anti-anxiety effects in bipolar treatment without triggering manic episodes.Limited human data
- Increases the growth of skin fibroblasts (the cells that build skin structure) and delays those cells ageing. Applied to skin it improves skin viability, wound healing, hydration, thickness of the deeper skin layer, and the genes governing the skin's structural proteins.Animal or lab only
- Shows superior absorption of UVA and UVB light and protects against DNA damage.Animal or lab only
- For people with chronic idiopathic pruritus ani — persistent itching and discomfort around the anus that has not responded to standard treatment — injections of a 1% methylene blue solution resolved symptoms within four weeks, with a very high success rate and no serious side effects.Limited human data
- Effective in treating malaria, urinary tract infections, shock, and methemoglobinemia. It has been called the only known substance able to restrain excessive production of reactive species and cytokines, and suggests potential in treating COVID-19 and SARS-CoV-2 infection.Limited human data
- A particularly effective antiviral for flavivirus infections, especially Zika virus.Animal or lab only
- Is an anticancer agent and promotes apoptosis — programmed cell death — in tumours.Animal or lab only
- For patients with oral mucositis, a painful complication of cancer therapy that affects eating and quality of life and can force treatment to be cut short, rinsing with Methylene Blue significantly reduced pain within the first three treatments.Limited human data
- Helps treat methemoglobinemia, a condition in which the blood cannot carry oxygen properly.Human trials
- Facilitates electron transfer in the mitochondrial respiratory chain, bypassing complex deficiencies and reducing oxidative stress — improving mitochondrial function, cellular energy production, and offering therapeutic potential in neurodegenerative conditions.Animal or lab only
- Direct antioxidant activity: free-radical neutralisation, protection from oxidative stress.Animal or lab only
- Nitric oxide modulation with cardiovascular and blood-flow consequences.Animal or lab only
- Neuroprotection through preservation of neuronal viability and function.Animal or lab only
- Cognitive enhancement via increased cerebral blood flow, with improved memory and attention.Limited human data
- Antimicrobial activity disrupting bacterial and microbial function, as an adjunct to conventional therapy.Limited human data
- Lipophilicity permitting efficient blood-brain barrier penetration, with high brain concentration observed post-dose.Animal or lab only
- Counteracts premature cellular senescence and ageing.Animal or lab only
- Reduces markers of ageing in cellular tissue.Animal or lab only
- Reduces amyloid-binding alcohol dehydrogenase (ABAD) while increasing estradiol levels.Animal or lab only
- Mitigates symptoms of hepatic encephalopathy.Animal or lab only
- Acts through macroautophagy to protect neurons from death under nutrient deprivation.Animal or lab only
- Antidote for cyanide and carbon monoxide poisoning.Animal or lab only
- Treatment of urinary tract infections.Limited human data
- Reduces mortality in postoperative vasoplegia / vasoplegic syndrome following cardiac surgery.Human trials
- Septic shock management.Human trials
- Substantially reduces morbidity and mortality in paediatric shock refractory to fluid and catecholamine therapy.Limited human data
- Increases mean arterial pressure in septic shock, reducing adjunct medication requirement, length of stay, and improving cardiac function and oxygenation.Human trials
- Treatment of psychotic and mood disorders; memory enhancement in fear-extinction training; promise in short- and long-term bipolar treatment, with antidepressant and anxiolytic effects and without induction of mania.Limited human data
- Enhances dermal fibroblast proliferation and delays fibroblast senescence; topical application improves skin viability, wound healing, hydration, dermal thickness, and extracellular matrix protein gene expression.Animal or lab only
- Superior UVA and UVB absorption with protection against DNA damage.Animal or lab only
- Chronic refractory idiopathic pruritus ani: intradermal 1% methylene blue to the dentate line resolved symptoms within four weeks at high success rate without serious adverse effects.Limited human data
- Efficacy in malaria, urinary tract infection, shock, and methemoglobinemia; described as the only known substance capable of restraining excessive reactive-species and cytokine generation, with suggested application to COVID-19 and SARS-CoV-2.Limited human data
- Antiviral activity against flaviviruses, particularly Zika.Animal or lab only
- Anticancer activity, promoting apoptosis in tumours.Animal or lab only
- Oral mucositis: methylene blue rinse produced significant pain reduction within the first three treatments.Limited human data
- Treatment of methemoglobinemia.Human trials
Reconstitution and dosing
One 25 mg pill per day, every day. There is no titration or build-up.
Run a 4 to 8 week cycle, then take 2 to 4 weeks off.
Dose in the morning. For the strongest mitochondrial and cognitive effect, take it lightly fasted — meaning without a full meal beforehand.
One practical note that follows from the side-effect list: your urine, tongue, and saliva will very likely turn blue or green. That is expected, not a problem.
Fixed dose, no titration: 1 × 25 mg pill daily, 7 days per week.
Cycle 4–8 weeks with a 2–4 week washout.
Morning dosing; lightly fasted for maximum mitochondrial and cognitive effect.
Context for the dose: 25 mg/day is at the low, nootropic end of the methylene blue range — clinical methemoglobinemia dosing is 1–2 mg/kg intravenously, and the hormetic dose-response for cognitive effects is well documented, with higher doses reversing the benefit. The low fixed dose is consistent with that biphasic curve.
No MAOI washout period has been established despite the serotonergic contraindication, which is the most significant gap in this protocol.
Oral pills — 25 mg per pill
Cycle: 4–8 week cycle followed by a 2–4 week washout · Frequency: Daily; dose in the morning; take lightly fasted for maximum mitochondrial and cognitive benefit
| When | Dose | How often |
|---|---|---|
| Whole cycle | 1 pill (25 mg) | once per day, in the morning |
Who should avoid it
- Anyone pregnant or breastfeeding.
- Anyone with **G6PD deficiency** — glucose-6-phosphate dehydrogenase deficiency, a genetic condition that stops red blood cells protecting themselves from oxidative stress. Methylene Blue can destroy red blood cells in these people, causing haemolytic anaemia.
- Anyone currently taking, or who has recently taken, SSRIs (selective serotonin reuptake inhibitors), SNRIs (serotonin-norepinephrine reuptake inhibitors), tricyclic antidepressants, or MAO inhibitors — all classes of antidepressant. Combining them with Methylene Blue can cause serotonin syndrome.
- From the combination entry that pairs Methylene Blue with Dihexa and Tesofensine: anyone with severe liver or kidney disease or dysfunction, because those organs cannot break the compound down and clear it, so it builds up.
- There are eight known drug interactions, and you should read all of them before taking this. The first is **serotonin-raising drugs**: SSRIs, SNRIs, tricyclic antidepressants, and MAOIs can cause serotonin syndrome when combined with Methylene Blue.
- **Antidepressants and MAO inhibitors.** Because Methylene Blue blocks MAO-A (an enzyme that breaks down serotonin), combining it with an MAO inhibitor such as phenelzine or tranylcypromine raises the risk of a hypertensive crisis — a dangerous spike in blood pressure — as well as serotonin syndrome.
- **Other MAO inhibitors**, including ones not used as antidepressants, such as selegiline. Same risks: hypertensive crisis and serotonin syndrome.
- **Blood thinners and antiplatelet drugs.** Methylene Blue may affect how platelets clump and how blood clots. Take care with warfarin or heparin, since it may increase bleeding risk — though this is more commonly seen with intravenous use.
- **Stimulant drugs that act on adrenaline pathways**, such as epinephrine, dopamine, amphetamine, or pseudoephedrine. Combining them raises the risk of high blood pressure and a fast heart rate.
- **Drugs that affect the liver enzyme CYP1A2.** Methylene Blue is broken down by this enzyme, so drugs that block it (such as ciprofloxacin) or speed it up (such as carbamazepine) can change how much of it is in your system.
- **Dantrolene**, a drug used for malignant hyperthermia. Methylene Blue can make dantrolene less effective at treating that rare but serious condition.
- **Caffeine.** Caffeine and Methylene Blue can add up in stimulating the nervous system, making nervousness, insomnia, or a fast heart rate more likely.
- Talk to a doctor before starting, and go through your full medication list with them. This compound has more medication interactions than almost anything else on this site.
- Pregnancy or breastfeeding.
- G6PD deficiency — risk of haemolytic anaemia, since the erythrocytes cannot regenerate NADPH to buffer the oxidative load.
- Active or recent use of SSRIs, SNRIs, tricyclic antidepressants, or MAO inhibitors — concurrent use can precipitate serotonin syndrome.
- From the Dihexa/Methylene Blue/Tesofensine combination entry on this site: severe hepatic or renal disease or dysfunction, given increased toxicity risk from impaired metabolism and elimination. This item is specific to the combination entry.
- Eight interactions are documented, beginning with serotonergic drugs: SSRIs, SNRIs, tricyclic antidepressants, and MAOIs — serotonin syndrome.
- Antidepressants: MAO-A inhibition means co-administration with MAOIs (phenelzine, tranylcypromine) raises the risk of hypertensive crisis and serotonin syndrome.
- Other MAO inhibitors, including non-antidepressant agents such as selegiline — same hypertensive-crisis and serotonin-syndrome risk.
- Anticoagulants and antiplatelet drugs: possible effect on platelet aggregation and coagulation; caution with warfarin or heparin for bleeding risk, more commonly reported with intravenous administration.
- Sympathomimetics (epinephrine, dopamine, amphetamine, pseudoephedrine): increased risk of hypertension and tachycardia through additive adrenergic stimulation.
- CYP1A2 inhibitors and inducers: methylene blue is a CYP1A2 substrate, so inhibitors (ciprofloxacin) and inducers (carbamazepine) alter drug levels and effect.
- Dantrolene: methylene blue can reduce dantrolene's effectiveness in malignant hyperthermia.
- Caffeine: synergistic CNS stimulation, increasing nervousness, insomnia, and tachycardia.
- Practical note: the interaction list here is the longest of any compound on this site, and the serotonergic one is the one that kills. MAOI washout periods are conventionally measured in weeks, not days — no washout guidance has been established here, which is a notable gap.
Side effects
- Mild nausea.
- Blue or green urine.
- Blue or green tongue and saliva.
- Headache.
- Insomnia — difficulty sleeping.
- Restlessness.
- Sweating.
- Dizziness.
- Anxiety or jitteriness.
- A fast heart rate.
- Raised blood pressure.
- Tremor — shaking.
- Overactive reflexes.
- Agitation.
- Haemolytic anaemia — the destruction of red blood cells. Methylene Blue increases oxidative stress in red blood cells that lack the protective molecule NADPH. This is particularly a risk for anyone with G6PD deficiency, a condition that makes red blood cells more vulnerable to oxidative stress.
- **Serotonin syndrome.** Methylene Blue blocks MAO-A, an enzyme that breaks down serotonin. Combined with other drugs that raise serotonin — SSRIs, SNRIs, MAOIs, tricyclic antidepressants — it can trigger this. Symptoms include: overheating, agitation, increased reflexes, tremors, muscle rigidity, confusion or delirium, a fast heart rate, seizures, and swings in blood pressure. This is a medical emergency.
- **Methemoglobinemia.** Methylene Blue is used to treat this condition, but overuse or the wrong dose can make it worse in some situations, particularly in people who have other blood disorders, and the result is that the blood cannot deliver enough oxygen.
- **Heart and blood vessel problems.** A fast heart rate and high blood pressure can occur, especially at high doses or in people who already have a heart condition.
- **Nerve toxicity.** Seizures, confusion, or psychosis can occur at very high doses, particularly when given intravenously or used off-label for brain protection or cognitive enhancement.
- Mild nausea.
- Blue/green urine.
- Blue/green tongue and saliva.
- Headache.
- Insomnia.
- Restlessness.
- Sweating.
- Dizziness.
- Anxiety / jitteriness.
- Tachycardia.
- Elevated blood pressure.
- Tremor.
- Hyperreflexia.
- Agitation.
- Haemolytic anaemia: methylene blue increases oxidative stress in erythrocytes lacking NADPH protection, and can induce haemolysis particularly in G6PD deficiency.
- Serotonin syndrome: MAO-A inhibition combined with serotonergic agents (SSRIs, SNRIs, MAOIs, tricyclics). Listed features: hyperthermia, agitation, hyperreflexia, tremor, muscle rigidity, confusion or delirium, tachycardia, seizures, blood-pressure lability. Note the overlap with the plain side-effect items above — tremor, hyperreflexia, agitation, tachycardia, sweating all appear in both lists, which makes early serotonin syndrome hard to distinguish from ordinary tolerability at dose.
- Methemoglobinemia: paradoxically inducible despite being the treatment for it, on overuse or inappropriate dosing, especially with concurrent blood disorders, leading to inadequate oxygenation.
- Cardiovascular: tachycardia and hypertension, especially at high dose or with pre-existing cardiac disease.
- Neurotoxicity: seizures, confusion, or psychosis at very high doses, particularly intravenous or off-label neuroprotective / cognitive-enhancement use.
User reports
User reports are individual experiences submitted by site visitors. They are not medical advice, are not verified for accuracy, and do not reflect Amino Reference's views. Read the evidence section above and talk to a clinician. Full disclaimer.
Stacking
A combination capsule on this site that contains Methylene Blue at 50 mg — double the dose on this page — alongside two other compounds. Its entry also lists one contraindication not listed here: severe liver or kidney disease. If you are considering that blend, note that Tesofensine raises serotonin and Methylene Blue blocks the enzyme that breaks serotonin down.
The combination product on this site, at 50 mg methylene blue — twice this page's dose — with dihexa 5 mg and tesofensine 500 mcg. That entry adds severe hepatic or renal dysfunction to the contraindication list. It also pairs an MAO-A inhibitor with a serotonin reuptake inhibitor in one capsule, which is the exact combination this page's own interaction section warns against; the blend entry does not reconcile that.
The nootropic — a compound taken for thinking and memory — that appears alongside Methylene Blue in that combination capsule. Its own entry warns about combining it with MAO inhibitors, and Methylene Blue is one.
The other cognitive component of the combination capsule. Its interactions section flags MAO inhibitors under dopaminergic amplification, with agitation, insomnia, and sympathetic activation — methylene blue qualifies as an MAO-A inhibitor, so the pairing is one its own interaction list cautions about.
Dosing figures have been reviewed and units are recomputed from the stated protocol.