Methylene blue
Checked Oct 11, 2026 · 8 sources checked
Methylene blue is a blue dye that is also a prescription drug. Given into a vein, it treats acquired methemoglobinemia, a blood problem in which blood cannot carry oxygen well. The FDA first approved the brand ProvayBlue for this in 2016 under its accelerated-approval pathway, and generic injections since 2023. Its label carries a boxed warning: combined with many antidepressants or opioids, it can cause serotonin syndrome, which can be fatal. It can also make pulse-oximeter readings wrong. Its label says people with G6PD deficiency, an inherited enzyme condition, should not receive it. In them, it can break down red blood cells. Online, it is promoted for memory, energy and aging. Human evidence for those uses is limited to small, short studies. A related drug was tested in large Alzheimer's trials, which missed their main goals.
Education only, not medical advice. Talk to a clinician about your own situation.
Attention is high but mixed. English Wikipedia's Methylene blue article had 27,929 views in September 2026. PubMed added 125 records in the 30 days to Oct 11 2026, but most concern its use as a dye in surgery, imaging or chemistry, not brain health.
In a randomized trial of 26 healthy adults, one low oral dose of methylene blue changed brain activity on MRI during attention and memory tasks and was linked to 7% more correct memory answers one hour later.
Does methylene blue improve memory, energy or healthy aging in people?
If a registered randomized trial lasting months shows a meaningful cognitive benefit in healthy or older adults, we would add it to the opening and re-grade the "not shown" line.
If FDA issues a new safety communication on non-prescription methylene blue products, we would add it to the safety sentence.
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Maturity: source checked
In a randomized trial of 26 healthy adults, one low oral dose of methylene blue changed brain activity on MRI during attention and memory tasks and was linked to 7% more correct memory answers one hour later.
Healthy adults aged 22-62 · Outcome: fMRI task response; memory retrieval accuracyConfidence applies to this claim and context.
Checked facts
- In a randomized trial of 26 healthy adults, one low oral dose of methylene blue changed brain activity on MRI during attention and memory tasks and was linked to 7% more correct memory answers one hour later. PMID 27351678 ↗
- In septic shock, a single-center trial of 91 patients found that intravenous methylene blue shortened time on blood-pressure drugs (69 vs 94 hours). A meta-analysis of six small trials found possible lower short-term mortality, rated low certainty. PMID 36915146 ↗
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Claims
Mapped studies / experiment families
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Studies & active trials
Only papers and registered trials an editor reviewed for this page. Being listed is not a finding; the claims above say what they show.
What still isn't settled?
Does methylene blue improve memory, energy or healthy aging in people?
Human data are limited to small, single-dose imaging studies. A related compound did not slow Alzheimer's decline in large trials. A ClinicalTrials.gov search on 2026-10-11 found no active trial of methylene blue for cognition, memory or dementia.
What would answer it: A registered, randomized, placebo-controlled trial of at least several months measuring cognition or function, with safety monitoring for serotonin syndrome.
Established: intravenous methylene blue is an FDA-approved treatment for acquired methemoglobinemia, and it can cause serotonin syndrome with serotonergic drugs and opioids. Not shown: that methylene blue improves memory, energy or aging in people. Only small, short studies exist.