Methylene Blue — Body Handbook

Supplements · §523

Methylene Blue

A 150-year-old textile dye, sold by compounding pharmacies in dropper bottles, that genuinely sharpens an hour of attention — and will land you in the ER if you take it on an antidepressant. Methylene blue is the rare supplement with real biochemistry behind it: it carries electrons directly inside your mitochondria, the cellular engines that make ATP. The cognitive effect is real and modest; the marketing around it is enormous. The two questions that matter are how to dose it without flipping the curve, and whether one of the contraindications applies to you.

Do · Daily Evidence Mixed Chapter Supplements

A few drops in water buys you a measurably sharper hour of attention and short-term recall — a 7% memory-retrieval bump on imaging, not a transformation. Cheap, low-effort, with a hundred-year safety record at proper dose. The catches are sharp: if you're on an SSRI or any antidepressant, methylene blue can trigger fatal serotonin syndrome, and if you have undiagnosed G6PD deficiency it can put you in haemolytic crisis. Get pharmaceutical-grade — the aquarium and lab grades carry heavy-metal contamination at levels you do not want chronically.

Inside every cell, mitochondria run a kind of bucket-brigade: electrons get passed down a chain of four protein complexes, and at the end of the chain that energy is used to make ATP, the body's universal currency. Methylene blue does something almost no other ingestible compound does — it joins the chain. The molecule cycles between two forms, blue and colourless, picking electrons up early in the chain and handing them off near the end, bypassing the two middle steps where most age-related and disease-related bottlenecks occur Wen 2011. The downstream consequences earn most of the cognitive and longevity claims: complex IV activity rises by about 30%, cellular oxygen consumption rises 37–70%, and the cell makes more ATP Atamna 2008.

There is a second mechanism that matters. Electrons that escape the chain react with oxygen to form superoxide, a damaging free radical implicated in ageing and neurodegeneration. By accepting those electrons early, methylene blue prevents the escape — and the byproduct it produces, hydrogen peroxide, is something cells already know how to neutralise. The molecule acts as a catalytic antioxidant rather than a sacrificial one: a single molecule keeps cycling, mopping up many oxidations rather than being used up in one Rojas 2012.

What the trials actually show

The cleanest human trial is small but well-designed. Twenty-six healthy adults, ages 22 to 62, took either a single 280 mg dose of pharmaceutical methylene blue or placebo, blinded, then ran through attention and short-term memory tasks inside an fMRI scanner one hour later Rodriguez 2016. The methylene blue group showed measurably more activity in attention-related brain regions during sustained-attention tasks, and recalled 7% more correctly during the memory task. Not a transformation. A real, measurable, single-dose bump.

The mood evidence is older and tighter to a specific population. Two double-blind trials of methylene blue added on top of standard mood stabilisers in bipolar disorder — Naylor's two-year crossover in the 1980s and Alda's six-month crossover in 2017 — both showed significant reductions in residual depression and anxiety scores at active doses of 195–300 mg per day Naylor 1987, Alda 2017. The signal is real but tied to bipolar patients already on lithium or lamotrigine; healthy people taking methylene blue for general mood lift are extrapolating well beyond what the data show.

The biggest trial of all was the failure: TauRx's phase 3 programme tested a reduced derivative of methylene blue called LMTM in mild-to-moderate Alzheimer's disease across thousands of patients, and found no difference from placebo on the standard cognitive or functional scales Gauthier 2016. That trial collapsed the dementia-prevention story that had been the main commercial narrative since 2008.

How to dose it

The hormetic curve dictates everything. The studied window is 0.5 to 4 mg per kilogram of bodyweight — for a typical 70 kg adult, that is roughly 5 to 40 mg. Above that ceiling, the molecule starts working against you; well above it, you risk iatrogenic methemoglobinemia (the very condition methylene blue normally treats). Start at the bottom of the range and stay there unless you have a reason to climb.

Expect bright blue-green urine within hours of dosing. It is harmless, lasts as long as the dose is being cleared, and is the easiest way to confirm you actually took it. The tongue stains for an hour or two. Surfaces, clothing and porcelain stain semi-permanently — be careful where you set the bottle down.

The two ways this can hurt you

Methylene blue has been used clinically since the 1890s; the safety envelope is well-mapped. Two interactions sit outside that envelope and account for almost every serious incident.

Beyond those two: don't use during pregnancy (fetal harm reported) or while breastfeeding (excreted in milk, will stain it). Severe kidney impairment is a reason to clear it with a clinician. Taking it under proper conditions, at the doses described here, has a long safety record — but the contraindications above are absolute, not "talk to your doctor about." If you are on an antidepressant, the right move is to skip this entry.

What the marketing gets wrong

Three things keep getting sold as true that aren't.

"Aquarium-grade is fine, it's the same molecule." No. Tested batches of non-pharmaceutical methylene blue carry 150–400 ppm zinc chloride and 10–50 ppm combined heavy metals — mercury, arsenic, lead — at levels that would fail any pharmaceutical safety test. Some batches run above 50% inorganic residues. For a one-off aquarium dose that isn't your problem; for daily ingestion, it is. Pay for the USP grade.

"If a little is good, more is better." Almost uniquely among supplements, this is the wrong direction with methylene blue. The dose-response is biphasic: the same molecule that boosts mitochondrial respiration at 1–4 mg/kg shuts it down above 10 mg/kg Bruchey 2008. People who scale the dose up because they "didn't feel anything" routinely land worse than where they started.

"It prevents Alzheimer's." This was the headline claim from 2008 onwards, based on early-phase work on tau aggregation Wischik 1996. The pharmaceutical version of that bet — LMTM, a chemically related derivative — ran phase 3 trials across thousands of patients and failed to slow cognitive or functional decline at any dose Gauthier 2016. The neuroprotective mechanism in cells is real Atamna 2008; whether oral low-dose methylene blue prevents dementia in humans is unproven and, after LMTM, viewed skeptically.

What you actually get

An hour after a low oral dose, an attention task you would have spaced through goes a little differently. The afternoon meeting where you usually reread the same sentence three times — you reread it once. People who try it for cognitive work do not describe it as stimulant-like; there is no jitter, no crash, no extra heart rate. It feels less like coffee and more like the version of your brain you have on a good night's sleep. The fMRI data underwrite the felt experience: real activation increases in the brain regions that handle sustained attention and recall, lasting a few hours Rodriguez 2016.

Day to week: the effect is acute, not cumulative. Skip a day and the bump is not there that day. Take it for a month and the average day looks a little sharper, but not in a way most users would notice without paying close attention.

Year and beyond: this is the speculative range. Cellular and animal work shows methylene blue delays mitochondrial decline and the senescence that comes with it Atamna 2008, Rojas 2012. No human trial has run long enough to show that translates into measurably less cognitive decline or measurably more healthspan. The mechanism is good enough to make the bet rational at this cost and effort; the human evidence is not good enough to make the bet certain.

A century and a half of uses

Heinrich Caro made the first batch at BASF in 1876, as a textile dye for cotton. Fifteen years later, Paul Ehrlich noticed that it stained malaria parasites preferentially and tried it as a treatment — methylene blue thereby became the first fully synthetic drug ever used clinically. It treated malaria through the Pacific theatre of the Second World War, urinary tract infections through the 1950s, and cyanide poisoning continuously since. The 1980s brought a brief psychiatric chapter via Naylor's bipolar trials Naylor 1987. The current cognitive-supplement era began in the 2000s with Gonzalez-Lima's lab characterising the mitochondrial mechanism and the sharp hormetic curve Rojas 2012. The Alzheimer's chapter, opened by Wischik in the 1990s on the tau-aggregation idea Wischik 1996, closed with the LMTM phase 3 failure in 2016 Gauthier 2016. The molecule outlives every wave of enthusiasm about it.

If the mitochondrial angle is what draws you here, two adjacent entries are worth looking at: creatine (an energy-buffer substrate for the same cellular machinery, with much stronger human evidence at much higher use volumes) and the broader class of NAD+ precursors. If the cognitive-enhancement angle is the draw, modafinil and the caffeine entries cover the better-evidenced competitors with different trade-offs. And if you came here from a podcast that included red-light therapy in the same conversation — the two are often paired in research, on the theory that near-infrared light and methylene blue act on the same cytochrome — that is a separate, longer story worth its own entry.

Substance + claimed effects

Methylene blue (methylthioninium chloride) is a synthetic phenothiazine dye, first synthesised by Heinrich Caro at BASF in 1876 as a textile colourant Schirmer 2011. Within twenty years it had become the first fully synthetic drug used clinically — Paul Ehrlich's antimalarial in the 1890s — and it has been in continuous medical use ever since. Today it is FDA-approved as an intravenous antidote for acquired methemoglobinemia (typical dose 1–2 mg/kg IV) and is increasingly used off-label, orally, at much lower milligram doses (0.5–4 mg/kg) as a cognitive / mitochondrial supplement.

Claimed effects worth covering in this entry, in roughly decreasing order of evidence strength: short-term memory and sustained attention enhancement in healthy adults Rodriguez 2016; reduction of residual depression and anxiety symptoms in bipolar disorder Alda 2017, Naylor 1987; neuroprotective effects against age-related mitochondrial decline Atamna 2008, Rojas 2012; facilitation of fear-extinction learning Telch 2014; and a general subjective energy / clarity uplift that the community reports broadly but that has not been formally trialled. Out of scope: the failed tau-aggregation programme in Alzheimer's (LMTM / TRx0237), which is a chemically related derivative rather than methylene blue itself; intravenous oncology and surgical-dye uses; and treatment of malaria.

Evidence by addressing question

mechanism

Methylene blue is unique among ingestible compounds in that it can shuttle electrons directly within the mitochondrial electron transport chain. The molecule alternates between an oxidised form (MB+, blue) and a reduced form (leucomethylene blue, MBH, colourless), accepting electrons from NADH and donating them onward to cytochrome c — effectively bypassing complexes I–III and feeding electrons directly into complex IV (cytochrome c oxidase) Wen 2011, Rojas 2012. The result is increased cytochrome oxidase activity (≈30% in neuronal mitochondria), increased cellular oxygen consumption (37–70%), and increased ATP production Atamna 2008.

Two downstream consequences earn the cognitive and neuroprotective claims. First, by accepting electrons before they can leak to molecular oxygen, methylene blue reduces superoxide production — it acts as a catalytic redox antioxidant rather than a sacrificial one Rojas 2012. Second, the auto-oxidation product is hydrogen peroxide rather than superoxide; cells detoxify H₂O₂ readily via catalase / glutathione peroxidase, so the net oxidative load drops.

Crucially, the effect is hormetic: stimulatory at low doses (1–4 mg/kg in animal models) and inhibitory at higher doses (above ~10 mg/kg) Bruchey 2008, Rojas 2012. The biphasic curve is well-characterised across behavioural, physiological and biochemical endpoints — at high concentrations methylene blue flips from electron donor to electron sink and impairs the very respiration it enhanced at low dose. This means dosing matters more than for almost any other supplement: too much is worse than none.

evidence

The strongest human trial is Rodriguez et al. (2016), a double-blind, placebo-controlled, randomised fMRI study in 26 healthy adults aged 22–62. A single oral dose of 280 mg (≈4 mg/kg) USP methylene blue produced significant fMRI activation increases in the bilateral insular cortex during a psychomotor vigilance (sustained attention) task and across prefrontal / parietal / occipital cortex during a short-term memory task, with a 7% improvement in memory retrieval accuracy versus placebo Rodriguez 2016. The effect size is modest but the design (within-subject crossover, blinded) is clean.

Telch et al. (2014) randomised 42 adults with claustrophobia to 260 mg methylene blue or placebo immediately after exposure-therapy sessions Telch 2014. The headline result was conditional: participants who had achieved good extinction during the session showed significantly less return-of-fear at one-month follow-up if they had received methylene blue, but participants with poor extinction tended to do worse — methylene blue consolidates whatever memory was laid down during training, beneficial or otherwise. This is consistent with the literature's broader memory-consolidation framing.

For mood, Naylor's bipolar trials (1986, 1987) are the originals: a two-year crossover comparing 15 mg/day versus 300 mg/day methylene blue in lithium-treated bipolar patients found significantly less depression on the active dose Naylor 1987. Alda et al. (2017) replicated and extended this: a six-month double-blind crossover in 37 bipolar patients on lamotrigine compared 195 mg/day active dose versus 15 mg/day "placebo", finding significant improvements on MADRS (P = 0.02), HAM-D (P = 0.05), and HAM-A anxiety (P = 0.02); cognition did not improve Alda 2017. Mania was unchanged. The mood-stabilising signal is real but the trials are small and confined to bipolar patients on lithium or lamotrigine — not generalisable to healthy users seeking a mood lift.

For Alzheimer's, the LMTM phase 3 programme — methylthioninium itself in its reduced form (leucomethylthioninium-bis(hydromethanesulfonate)) — failed comprehensively in 2016. Gauthier et al. found no significant difference on ADAS-Cog or ADCS-ADL between 150–250 mg/day LMTM and placebo (where placebo was 8 mg/day LMTM, complicating the read) Gauthier 2016. TauRx published controversial subgroup reanalyses suggesting monotherapy benefit, but the consensus is that LMTM did not work. This shapes how the broader Alzheimer-prevention claim should be weighted.

protocol

Off-label oral nootropic dosing is conventionally 0.5–4 mg/kg, daily or as needed. The community standard for healthy adults is to start at 0.5–1 mg/kg (roughly 5–10 mg for a 70 kg adult) and titrate up. The Rodriguez 2016 single-dose protocol of 4 mg/kg is near the top of the hormetic window; doses above 5 mg/kg push into the inhibitory limb and risk methemoglobinemia paradoxically. Pharmaceutical USP grade is the only form considered safe for ingestion — industrial / aquarium / textile grades may contain up to ~11% heavy-metal contaminants (mercury, arsenic, lead, zinc chloride). Taken with vitamin C is common to keep the molecule reduced and reduce gastric irritation. Stains everything blue: teeth (transient), tongue, urine (bright blue-green, harmless), and surfaces; oral drops typically taken diluted in water through a straw.

contraindications

Two serious contraindications dominate. First, serotonergic medications: methylene blue is a potent reversible monoamine oxidase inhibitor (MAO-A IC₅₀ in the low nanomolar range), and co-administration with SSRIs, SNRIs, tricyclic antidepressants, MAOIs, bupropion, mirtazapine, or any serotonergic agent can precipitate serotonin syndrome, sometimes fatal. The FDA issued a Drug Safety Communication on 2011-07-26 (updated 2011-10-20) explicitly warning against this combination FDA 2011; at least 14 case reports of probable or definite serotonin toxicity, one fatal, are documented. The interaction is dose-dependent but real even at oral nootropic doses. Second, G6PD deficiency: methylene blue requires NADPH from the pentose phosphate pathway to be reduced; in G6PD-deficient patients it instead drives oxidative haemolysis and paradoxically worsens methemoglobinemia. Other contraindications: pregnancy (FDA category C/X — fetal harm in animal studies and human reports); breastfeeding (excreted in milk, stains it); severe renal impairment.

misconceptions

Three keep recurring. (1) "Aquarium-grade is fine, it's the same molecule." Lab and aquarium grades commonly carry 150–400 ppm zinc chloride and 10–50 ppm combined heavy metals, with some batches above 50% inorganic residues. Chronic ingestion at supplement doses concentrates this. USP grade is the bright line. (2) "If a little is good, more is better." The hormetic curve is unusually sharp for methylene blue: doses above ~10 mg/kg in animal models reverse the cognitive effect Bruchey 2008, and doses above ~5 mg/kg in humans can cause iatrogenic methemoglobinemia. (3) "It treats Alzheimer's." The LMTM phase 3 trials decisively did not show this Gauthier 2016; the consumer methylene blue products marketed for "brain health" are riding the hype of an earlier subgroup re-analysis that was not replicated.

practicalities

USP pharmaceutical-grade methylene blue solution (typically 1% w/v, i.e. 10 mg/ml) is available from compounding pharmacies and a handful of supplement vendors with third-party assays. Cost is modest — $30–80 for a 30 ml bottle that lasts months at low dose. Stains: teeth and tongue blue (rinses off teeth, lingers a few hours on tongue), surfaces and porcelain semi-permanently, clothing absolutely. Urine turns vivid blue-green for hours after a dose — harmless but startling. Many users take through a glass straw and follow with water.

stakes

For the healthy adult target reader, the realistic stakes of not taking methylene blue are: a small forgone cognitive bump (≈7% memory retrieval, transient) and continued exposure to the slow age-related decline in mitochondrial complex IV activity that animal and cellular studies suggest methylene blue could partially counter Atamna 2008, Atamna 2010. The decline is real; whether oral methylene blue meaningfully slows it in humans is unproven. The stakes of inappropriate use are sharper: serotonin syndrome (potentially fatal) if combined with common antidepressants, haemolytic crisis if combined with undiagnosed G6PD deficiency, and chronic heavy-metal accumulation from non-USP products.

payoff

The honest payoff at the low-dose nootropic protocol is a modest, measurable cognitive bump — sharper sustained attention, slightly better short-term memory recall — within an hour of dosing, with effect tailing off over the day Rodriguez 2016. Subjectively, many users report afternoon clarity that does not feel stimulant-like (no jitter, no crash). The longer-term mitochondrial / neuroprotective payoff is theoretical: mechanism is robust, cellular and animal data are strong Atamna 2008, Rojas 2012, but no human trial has run long enough to demonstrate prevention of cognitive decline.

history

Synthesised by Heinrich Caro at BASF in 1876 as a textile dye; first applied therapeutically by Paul Ehrlich and Paul Guttmann in 1891 for malaria, making methylene blue the world's first fully synthetic drug. Used extensively for urinary tract infections, malaria, and cyanide poisoning through the early 20th century. Reborn in psychiatry in the 1980s via Naylor's bipolar trials Naylor 1987, and again in the 2000s as a cognitive supplement following work from Gonzalez-Lima's lab characterising the hormetic mitochondrial mechanism. The tau-aggregation hypothesis (Wischik 1996) launched the TauRx Alzheimer's programme Wischik 1996, which dominated headlines from 2008 to the 2016 phase 3 failure Gauthier 2016.

alternatives

Other mitochondrial-targeted small molecules (CoQ10, PQQ, MitoQ, NAD+ precursors like NR and NMN) and other cognitive enhancers (caffeine, modafinil) compete for the same use case but work through different mechanisms. Methylene blue's distinguishing claim is that it is the only one that directly carries electrons in the respiratory chain rather than supplying a substrate. None of the alternatives carries the serotonergic-medication contraindication.

The credibility range

Optimist case. Methylene blue has an exceptionally well-characterised mechanism — alternative electron transfer is established biochemistry — and a hormetic dose response replicated across species and endpoints Rojas 2012, Bruchey 2008. There is a clean, placebo-controlled human fMRI trial showing measurable cognitive enhancement at a single low dose Rodriguez 2016, replicable mood-stabilising effects in two independent bipolar RCTs decades apart Naylor 1987, Alda 2017, and cellular evidence of senescence delay and complex IV upregulation Atamna 2008. A century of clinical use means the safety profile (within the contraindication envelope) is exceptionally well-mapped. The mainstream's reluctance is mostly an artefact of the molecule being off-patent and unprofitable to trial at scale — not a sign the effects aren't real.

Skeptic case. The cognitive evidence in healthy humans rests on a single small trial (n=26) with a transient ~7% retrieval improvement — not nothing, but not transformative either, and not yet replicated Rodriguez 2016. The high-profile Alzheimer's programme (LMTM) failed phase 3, hard Gauthier 2016. The mood data are confined to bipolar patients on existing mood stabilisers and don't generalise. The longevity / neuroprotection case is currently entirely mechanistic and animal — no human RCT has shown reduced cognitive decline or extended healthspan. Most "evidence" reaching consumers is mechanism-cherry-picking and case reports laundered through influencer content. The contraindication envelope (MAOI interaction, G6PD) is genuinely dangerous, and the supplement-grade supply chain has serious quality-control problems. A century of safe IV use at proper dose does not transfer to chronic oral self-dosing at home.

Author's call. Methylene blue is real but modest. The mechanism is well-evidenced, the acute cognitive effect in healthy adults is genuine and measurable but small, and the neuroprotective / longevity story is a plausible-but-unproven extrapolation from cell and animal work. The right framing is a low-cost, low-effort nootropic with a sharply defined safe-use envelope — worth trying if the contraindications are clear, not worth pushing as a transformative intervention. Evidence rating settles at 2/5 (real mechanism, small RCTs, no large replications, failed flagship trial in dementia); controversy at 3/5 (genuine community / mainstream split, with the LMTM failure as a flashpoint). The article should lean factual and contraindication-forward rather than aspirational.

Stakeholder + incentive map

Supplement vendors and compounding pharmacies — strong commercial incentive to talk up the cognitive / longevity story; mixed quality control between USP and industrial-grade product.
Biohacker / podcast subculture — high-volume amplifier of methylene blue as a "mitochondrial unlock", typically without engaging with the MAOI contraindication.
Mainstream neurology / psychiatry — historically dismissive after the LMTM failure; cautious about the MAOI interaction; not actively researching low-dose oral use because the molecule is off-patent.
Gonzalez-Lima lab (UT Austin) and collaborators — the academic anchor for the cognitive / mitochondrial line of research; published most of the foundational hormesis and human imaging work.
TauRx Therapeutics — sunk-cost stake in the LMTM derivative; has continued to argue subgroup positive results post-failure.
FDA — maintains methylene blue's approval as an IV antidote and has actively warned about the serotonergic-drug interaction FDA 2011.

Population variability

Patients on serotonergic medications — absolute contraindication, regardless of dose.
G6PD-deficient individuals (~5% of men of Mediterranean, African or South Asian descent; lower in women) — absolute contraindication; an undiagnosed deficiency is the highest-risk failure mode.
Pregnant or breastfeeding — contraindicated.
Older adults with declining mitochondrial function — theoretically the population with the most to gain (the Atamna senescence-delay mechanism is age-dependent Atamna 2008), but the only well-trialled human age band is 22–62 in Rodriguez 2016.
Patients with mild cognitive impairment or early dementia — the failed LMTM programme suggests the dementia-prevention story does not translate; cautious framing required.
Healthy adults seeking a cognitive lift — the population the evidence best supports, but the effect size is modest.

Knowledge gaps

No long-duration human trial of low-dose oral methylene blue exists. The Rodriguez 2016 protocol is single-dose; the longest-running human study is Alda 2017's six-month bipolar crossover. Chronic-dosing safety data in healthy adults are entirely anecdotal. Whether the cellular complex IV upregulation observed by Atamna translates to measurable healthspan or cognitive-decline benefit in humans is unknown — and unlikely to be tested at scale because the molecule is off-patent. The right dose for healthy nootropic use has been characterised only across a wide hormetic window (0.5–4 mg/kg); no head-to-head dose-finding trial in healthy adults has narrowed this. Sex and age differences in pharmacokinetics are essentially unstudied. The interaction risk with subclinical (undiagnosed) G6PD heterozygosity, particularly in women, is poorly mapped.

Narrowing relative to the brief. The brief named cognition, mood, energy, and cellular oxidative function. The article covers all four. Mood is the thinnest treatment — the human RCT data are confined to bipolar adjunctive use; rather than over-extrapolate to "methylene blue lifts mood in healthy adults", the article and meta both anchor the mood claim to the bipolar trials and score conservatively (mood=2). Energy similarly: the mechanism gets the column inches, the felt-effect claim stays modest.

Hard scoping calls.

Excluded the LMTM/TRx0237 phase 3 details beyond the headline failure result. The molecule is a derivative (leuco-methylthioninium-bis-hydromethanesulfonate), not methylene blue per se, and the controversial subgroup reanalyses (Wilcock 2018, Schelter 2019) would consume disproportionate space relative to their bearing on the actual reader decision.
Excluded the malaria, surgical-dye, and methemoglobinemia-treatment uses. These are out of scope for a supplement-category entry; readers needing them are under clinical care.
Excluded the methylene-blue-plus-near-infrared-light synergy story (Rojas 2012; PMC4428125). The mechanism overlap is real but the human data on photobiomodulation as a paired intervention is thin enough that it warrants its own entry rather than a paragraph here. Flagged in out-of-scope.
Did not include a stakes section. The substance is an optional cognitive supplement, not a deficiency or risk to address — the loss-aversion is structurally carried by contraindications instead.

Rating difficulties.

Focus: scored 3 on the strength of a single small RCT (n=26) with a 7% retrieval bump. A defensible 2 also exists; 3 reflects that the imaging endpoints and the behavioural endpoint moved in the same direction with a clean blinded design — small but coherent.
Evidence: scored 2. The mechanism is robust, but the cognitive trial base is one small RCT in healthy adults and two small bipolar trials. The Alzheimer's failure pulls the rating down further. 3 would imply broader replication that does not exist.
Controversy: scored 3 on the genuine community-vs-mainstream split. The LMTM failure is the flashpoint that prevents a lower score, the long safety history prevents a higher one.
Applicability: scored 1. Roughly 13% of US adults take antidepressants, all of whom are contraindicated. Add G6PD-deficient individuals, pregnant / breastfeeding women, and the addressable audience is realistically under 5%.
Contraindications token set: the closed vocabulary lacks tokens for "serotonergic medications" and "G6PD deficiency" — the two highest-priority contraindications for this substance. Pregnancy and breastfeeding capture some of the safety floor; the article body has to carry the rest. A future schema pass might add an SSRI/MAOI token and a G6PD token.

Future links / separate-entry candidates.

Near-infrared / red-light photobiomodulation as a standalone entry (mentioned in out-of-scope).
NAD+ precursors (NR, NMN) and CoQ10 as adjacent mitochondrial-targeted supplements; flagged but not yet cross-linked.
G6PD deficiency itself as a screening-category entry — relevant well beyond methylene blue.

Dream narrative. Computed overall score sits well below 40 (≈7 with applicability=1). Dream narrative written by choice on the relief lever — the reader's payoff is honest information about a substance the internet routinely oversells, plus a modest cognitive bump. Dek and tagline were written from it but kept calm and specific, not loud.