Methylene Blue dosage and evidence
Written by Aaron CuhaReviewed Sep 2026
The short answer
Methylene blue is an FDA-approved antidote for a rare blood problem called methemoglobinemia. Biohackers take small doses for energy and focus. The brain evidence is thin. It also blocks an enzyme called MAO, and taken with antidepressants it has caused serotonin syndrome, including a death.
Evidence grade for Methylene Blue: Limited. The rule: people have taken it in a published study, but fewer than 100 of them. The sum on this page: 1 completed trial, 26 people given it. A grade counts how much has been done to people, not whether it works.
- People given it
- 26
- Human studies
- 1
- Found nothing
- 0
Dose
Approved medicine. No human dose established for unlabelled uses
Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose.
FDA-approved only for methemoglobinemia (ProvayBlue), a blood problem where the blood cannot carry oxygen well; other uses are off-label or unapproved
7 effects reported, 5 unwanted, 2 wanted, by people using it, not a trial
Goal pages: Brain, memory and mood
In plain English
In plain English, from Aaron
This is how I would explain it to a friend. The evidence, with the numbers, is further down the page.
Methylene blue is an old blue dye that is also an approved antidote for a rare blood problem. Biohackers take small doses for energy and focus. It blocks an enzyme that breaks down serotonin. Mixed with antidepressants, that can be deadly.
What people take it for
- More energy, on the idea that it helps the cell's power plants.
- Better focus and memory.
- Brain health as you age.
What studies in people showed
The brain studies are small scans. In 26 healthy adults, one low dose changed brain activity during a task. That shows activity shifting, not anyone thinking better. Another scan study saw brain regions linking up differently, and nobody checked if that helped memory. A related drug failed to give clean results in Alzheimer's. The clear human finding is harm. At least 14 people taking antidepressants got serotonin syndrome, and one died.
What people report
Reports, not study results
The good
- Some describe better mood, clearer thinking and more energy within days to weeks.
- Some say it helps them handle hard conditioning work.
The bad
- Serotonin syndrome, including a death, in people also on SSRIs, SNRIs or similar drugs. Users repeat this warning more than any other.
- Diarrhoea, stomach upset, blue urine and stained teeth.
- Vivid dreams that break up sleep, and headaches at the start.
- Two to three months of use with nothing noticed, or an early lift that faded.
- Worry about aquarium or industrial grade product and heavy metals. People with G6PD deficiency should not take it at all.
Where these come from: Forum patterns from ExcelMale and LongeCity, as summed up on this page. Those are self-reports, not trial results. The serotonin syndrome cases come from the medical reports on this page.
My bottom line
If you take any antidepressant, stay away from this. Full stop. For everyone else, the brain benefit is a picture on a scanner, not something anyone has felt in a trial.
An opinion, not a finding. I am a coach, not a doctor.
What it has been measured to do
Measured in people
Goals Methylene Blue has been tested for in people, biggest studies first. We count only what the studies on this page say, so the real numbers may be higher.
- Memory and thinkingno headcount stated · 1 study
What people using it report
Real people telling you what happened to them. Nobody checked it, and the people who post are not a fair sample, so it cannot prove anything works. It is still the best guide on this page to what people actually do with Methylene Blue, what they expect, and what goes wrong. The full account, including the negative reports, is below.
31 of the 36 indexed goals have no study of any kind behind Methylene Blue
No study in people, animals or cells on this page reports a result for these. That does not prove Methylene Blue does nothing for them. It does mean anything you have heard about Methylene Blue and one of these did not come from a study cited here.
Show full evidence
What is Methylene Blue?
Methylene blue is an FDA-approved antidote for a rare blood problem called methemoglobinemia. Biohackers take small doses for energy and focus. The brain evidence is thin. It also blocks an enzyme called MAO, and taken with antidepressants it has caused serotonin syndrome, including a death.
Methylene blue is a dye and drug that has been around for about a century. At low doses it can help carry energy inside the cell's power plants, the mitochondria. In small brain scan studies in healthy adults, brain activity changed during memory tasks. A related drug, hydromethylthionine, did not give clean results in large final-stage Alzheimer's trials. Interest jumped in 2026 after public figures were seen drinking it.
Here is the danger. It strongly blocks an enzyme called MAO-A, even at doses well under 1 mg per kg of body weight. At least 14 published cases of serotonin syndrome, including a death, have happened in people also taking SSRIs, SNRIs or other drugs that raise serotonin. Serotonin syndrome is a dangerous overload of a brain chemical. People with G6PD deficiency, an inherited blood enzyme problem, should not take it. Products sold as supplements or aquarium dye are not drug grade.
How does Methylene Blue work?
It passes electrons along the energy chain inside mitochondria, the cell's power plants. It also blocks two enzymes for a while. One is monoamine oxidase A, which breaks down serotonin. The other makes nitric oxide.
What do people who took Methylene Blue report?
This is what real people say happened to them, good and bad. Nobody measured it. A report cannot tell a real effect from the lift people get just from expecting it to work, from a diet or training change made at the same time, or from what was really in the vial. We still put it near the top. It is the next best thing to a study in people: what happens when real people use it, including what goes wrong.
- Dose is the first thing people get wrong and the thing threads spend most time on. Amounts described run from a couple of milligrams to a hundred or more a day, and the repeated experience is that people settle far lower than they expected, often a few milligrams, and describe amounts above that as overstimulating rather than better. Body weight based figures taken from research are described as impractical at the scale people are using.
- Form matters to people. Dropper liquids are described as messy and as staining mouth and teeth, capsules are preferred for that reason, and taking it with a meal containing fat is the usual advice for stomach upset.
- Reported effects are mood, mental clarity and energy within days to weeks, vivid dreams, and better tolerance of conditioning work. Against that, people describe two to three months of consistent use with nothing noticeable, and others describe an early lift that did not last.
- Side effects described are diarrhoea and stomach discomfort, blue urine and staining, sleep broken by vivid dreams, and headaches at the start. A separate thread raises whether it could impair erections through an effect on nitric oxide, and nobody in it reports that happening, including at larger amounts.
- The warning people repeat most is about combining it with serotonergic prescription drugs, and those taking a monoamine oxidase inhibitor describe going very low and watching blood pressure.
- Sourcing is the other main concern. The distinction people draw is pharmaceutical grade against aquarium or industrial material, with heavy metal contamination as the specific worry, and at least one person describes stopping over purity doubts rather than over effects.
Sources: ExcelMale threads on the pros and cons and on a specific safety question, found by site-restricted search and read directly, September 2026, with LongeCity experience threads seen only through search extracts because that board timed out on direct fetch. Nothing above is attributed to any specific post and no post is reproduced.
The evidence, in charts
Fig. 1a · how many people
26people, across 1 study in people cited here
| Study | People | Share |
|---|---|---|
| Radiology 2016 | 26 | 100% |
The whole total is one study of 26. Counts are the number of people each study on this page says it signed up. That includes studies that only watched people and gave nobody the compound. 2 more studies in people give no headcount and are not counted here. Studies still signing people up are left out, and only studies cited on this page are counted.
Fig. 1b · evidence mix
3 of 4 sources here are studies in people. The rest is not.
- Study in people · done in people375%
- Review of studies · sums up other studies125%
Counted from the list of sources on this page. It counts only what we cite, so there may be more studies out there. A review counts once, however many studies it sums up.
Fig. 2 · evidence over time
The studies cover 4 different years, 2010 to 2018, counted from the list of sources on this page. The newest source on file is from 2018, more than five years ago. Research on it may have gone quiet.
Fig. 3 · legal status at a glance
US
Not approved
UK
Prescription
AU
Prescription
CA
Prescription
Approved in 0 of 4, by prescription in 3, not approved in 1. This is what the law says, not a verdict on the science. See Legal status below for the full text and any notes.
Fig. 5 · what the molecule is
- Kind of compound
- Small molecule
- Molecule weight
- 319.9 Da
- Half-life
- About 5.5 hoursShort, 1 to 6 hours
- Chain length
- None on file
No amino acid sequence is on file for Methylene Blue, which is expected: a small molecule is not built from amino acids.
The studies we cite
- Study in people2016Multimodal randomized functional MR imaging of the effects of methylene blue in the human brain
One low dose changed how the brain behaved during a task. 26 healthy adults were scanned while working. The scan shows brain activity shifting. It does not show anyone thinking faster or remembering more. Nothing a person would notice in daily life was measured.
A single low dose altered task-related brain activity in 26 healthy adults.
- Study in people2017Methylene blue modulates functional connectivity in the human brain
Methylene blue changed the way brain regions talked to each other on a scan. Nobody then checked whether that made any difference to memory, attention or anything a person would notice. A picture of the brain behaving differently is not a benefit until somebody measures one.
Connectivity changes; no clinical cognitive outcome.
- Study in people2010Serotonin syndrome from methylene blue with serotonergic drugs
This is the harm to know about. Patients already on antidepressants got serotonin syndrome after being given methylene blue. The drug acts on the same brain chemical those medicines do, and together they can make a person dangerously ill. These are real cases in real patients, not a risk worked out on paper.
Case series establishing the MAO-inhibitor interaction.
- Review of studies2018Methylene blue-associated serotonin toxicity: updated review
A 2018 review counted at least 14 cases of serotonin poisoning linked to methylene blue, including one death.
At least 14 cases including a fatality.
Where to buy Methylene Blue
Methylene Blue is an approved medicine. The approved product comes from a pharmacy, with a prescription. The vials below are sold “for research” and are not the approved drug.
6 sellers list Methylene Blue in our latest read. They are ranked by trust score, then by archive rating, then by certificate tier, then by the lowest price per milligram. Archive evidence is counted before source-backed. Each path is out of 4, and the two are not added. A higher price does not raise the score. The letter is the certificate chip. 0 of them have a published certificate that names Methylene Blue.
Some seller links may pay this site when you buy through them. A payment never changes a seller's tier or rank, and no seller has a say in any page.
| Seller | Trust score | Vial sizes | From, per mg | Certificate for Methylene Blue | Seller link |
|---|---|---|---|---|---|
| Iron Peptides | 49 WeakSource-backed 3 of 4. Archive evidence 2 of 4.A | 20 mg | $3.45 | None found for Methylene Blue | View |
| Sigma Compounds | 49 WeakSource-backed 3 of 4. Archive evidence 1 of 4.B | 10 mg | $4.70 | None found for Methylene Blue | View |
| SSP Research | 49 WeakSource-backed 2 of 4. Archive evidence 1 of 4.B | 10 mg | $5.00 | None found for Methylene Blue | View |
| APR Health Solutions | 40 WeakSource-backed 1 of 4. Archive evidence 1 of 4.C | 20 mg | $2.50 | None found for Methylene Blue | View |
| Modern Aminos | 28 InsufficientSource-backed 1 of 4. Archive evidence 0 of 4.C | 5 mg, 10 mg | $5.20 | None found for Methylene Blue | View |
| Pure Health Peptides | 25 InsufficientSource-backed 1 of 4. Archive evidence 0 of 4.C | 20 mg | $3.45 | None found for Methylene Blue | View |
- LC Lab-confirmed: the issuing laboratory echoed this certificate back
- A Current certificate, independent laboratory named, laboratory not yet checked
- B Certificate published, but no laboratory link, older than a year, or the laboratory did not recognise the published lookup
- C No certificate could be read
Every listing and vial size for Methylene Blue · How the trust score is counted
Sellers named on the price pages are ranked by certificate tier, then price, and any affiliate income is disclosed there. Naming a seller is not a recommendation to buy or use anything.
Common questions
Has Methylene Blue been tested in people?
Yes. 26 people given it across 1 completed trial cited here, 0 of which found nothing. Methylene blue is an FDA-approved antidote for a rare blood problem called methemoglobinemia. Biohackers take small doses for energy and focus. The brain evidence is thin. It also blocks an enzyme called MAO, and taken with antidepressants it has caused serotonin syndrome, including a death.
What is the Methylene Blue dosage?
Approved medicine. No human dose established for unlabelled uses. Labeled amounts sit on the prescribing information. This page records what trials measured, not a personal dose. FDA-approved only for methemoglobinemia (ProvayBlue), a blood problem where the blood cannot carry oxygen well; other uses are off-label or unapproved
Is Methylene Blue FDA-approved?
FDA-approved only for methemoglobinemia (ProvayBlue), a blood problem where the blood cannot carry oxygen well; other uses are off-label or unapproved
Can I take methylene blue with an SSRI?
No. It blocks monoamine oxidase and has caused serotonin syndrome, including a death, when taken with SSRIs, SNRIs and similar drugs. This is the most important fact about it.
Does it improve memory?
Small brain scan studies show brain activity changes after one dose. No trial shows a real memory benefit in healthy people, and the related Alzheimer's drug failed.
Latest reading on Methylene Blue
Blog posts about Methylene Blue, newest first.