Methylene Blue
Methylene blue is a small-molecule redox dye and an FDA-approved drug — marketed as PROVAYBLUE for intravenous treatment of acquired methemoglobinemia — that is separately studied at low oral doses for mitochondrial and cognitive effects. Research protocols in this catalog use 10 mg orally each morning, ranging 5-50 mg, and pharmaceutical or USP grade is mandatory.
Adults researching mitochondrial-electron-transport support or cognitive/attention effects at low oral doses. It is a drug, not a supplement: it carries a boxed warning for serotonin syndrome and is contraindicated in G6PD deficiency, so G6PD status and a full medication review come before any use.
Methylene blue (methylthioninium chloride) is a phenothiazine dye that behaves as a reversible electron carrier. In red blood cells it is reduced to leucomethylene blue by NADPH-methemoglobin reductase, and the reduced form then converts ferric methemoglobin back to functional ferrous hemoglobin — the basis for its FDA-approved use in acquired methemoglobinemia. That same redox behavior underlies the interest in it as a mitochondrial agent: at low concentrations it enters mitochondria and can cycle electrons between complex I and complex III, acting as an alternative electron carrier that bypasses damaged segments of the electron transport chain and increases cytochrome c oxidase activity and oxygen consumption.
The effect is concentration-dependent and reverses at higher doses, where methylene blue becomes an oxidant and inhibits rather than supports respiration — the reason low-dose framing is not a stylistic preference but a pharmacological requirement. Human evidence at low doses is limited but real: a randomized, double-blind, placebo-controlled functional MRI study in 26 healthy adults administered a single 280 mg (about 4 mg/kg) oral USP dose and reported increased fMRI response in bilateral insular cortex during a sustained-attention task, increased response in prefrontal, parietal, and occipital cortex during a short-term memory task, and a 7% increase in correct responses during memory retrieval. 3%.
The safety profile is the dominant fact. Methylene blue is a potent, reversible monoamine oxidase A inhibitor, and PROVAYBLUE carries a boxed warning that it may cause serious or fatal serotonin syndrome when combined with serotonergic drugs and opioids. It is contraindicated in G6PD deficiency, where it can cause severe hemolysis and anemia.
It also interferes with pulse oximetry readings.
Oral, once daily in the morning. The catalog reference starts at 10 mg per day with a range of 5-50 mg (10 mg start, 20 mg standard, 50 mg higher). Pharmaceutical or USP grade only — never laboratory or dye grade, which can carry heavy-metal contamination. The dose-response is hormetic: low doses and high doses have opposing effects, so more is not better. The FDA-approved indication uses a completely different regimen (1 mg/kg intravenously for methemoglobinemia) and is not what this ladder describes.
- Half-life
- ~24 h terminal (PROVAYBLUE intravenous label); approximately 40% excreted unchanged in urine
- Absorption
- Well absorbed orally; the FDA-approved product is intravenous
- Bioavailability
- Oral ~72% (absolute bioavailability, aqueous formulation, phase I crossover)
Acute and same-day. The human neuroimaging trial measured its effects one hour after a single oral dose. Urine and sometimes stool turn blue-green within hours — an expected, harmless marker that dosing occurred.
Discussed alongside mitochondrial-support protocols such as NAD+ and CoQ10, and with near-infrared light exposure in the photobiomodulation literature. The critical pairing rule runs the other way: it must not be combined with serotonergic medication (SSRIs, SNRIs, TCAs, MAOIs, triptans, tramadol, or other opioids) because of serotonin-syndrome risk.
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This page is educational reference material about compounds studied in research settings. It is not medical advice, and nothing here is a recommendation to buy, possess, or use any compound. Research findings described are from published literature; individual compounds may not be approved for human use. Talk to a licensed clinician about anything that affects your health.