FDA-approved in another form
FDA approved as an IV rescue drug. Sold online as a focus hack.
ProvayBlue, the only FDA-approved methylene blue, is an intravenous drug for a blood emergency called methemoglobinemia. The drops sold for brain fog are not an approved product, and the approved label now carries a boxed warning most wellness content never mentions: combined with common antidepressants or opioids, methylene blue can cause potentially fatal serotonin syndrome. We fetched and verified 38 sources so you can see what is proven, what is rat data, and who should never touch it.
- 38fetch-verified sources, every one peer-reviewed or government
- 22studies in the graded evidence table, species labeled on every row
- 18of those rows are human; the rat rows say rat
- 1FDA boxed warning, quoted in full on our safety page
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Key facts
- StatusFDA-approved in another form
- Absolute oral bioavailability72.3% (aqueous solution, n=16)
- Half-life (label)~24 hours
- Half-life (literature spread)5.25 h IV whole blood; 6-27 h delayed-release oral
- Urinary excretion~40% unchanged (label); blue-green urine expected
- Volume of distribution255 L steady-state (2 mg/kg IV)
- Protein binding~94% (in vitro)
- MetabolitesLeucomethylene blue (active reduced form); azure B (also a controlled impurity)
- Renal impairmentAUC +52% mild, +116% moderate, +192% severe; label halves dosing
- Oral formulation dependenceAqueous vs delayed-release shifts Tmax from hours to ~16 h
- ClassPhenothiazine-derived synthetic dye; oxidation-reduction agent
- Historical rankDescribed as the first synthetic drug in medicine
- Boxed warningSerotonin syndrome with serotonergic drugs and opioids; avoid SSRIs, SNRIs, MAOIs, opioids
- Hard contraindicationG6PD deficiency (hemolysis risk; drug may also not work); 1 of only 7 medications with solid prohibit-level evidence
- Approved dose1 mg/kg IV, maximum 2 doses (label)
- Toxicity bands3 mg/kg+ hypotension; 7 mg/kg+ cumulative causes paradoxical methemoglobinemia; 20 mg/kg+ hemolysis and death
- Oral bioavailability72.3% (aqueous solution)
- Urine effectBlue-green urine, expected and benign (~40% renal excretion of unchanged dye)
- Human cognition RCTsExactly one in healthy adults: single 280 mg dose, n=26, +7% memory retrieval accuracy
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Practical calculators and references, each scoped and sourced.
study rows by species, from the evidence table
All guides
63 in-depth, individually cited guides.
Safety 27 guides
Evidence 13 guides
Sourcing 9 guides
Comparisons 7 guides
Dosing 7 guides
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