Methylene Blue
Century-old dye and drug that shuttles electrons in mitochondria; low doses studied for Alzheimer's.
Summary
Debbie describes methylene blue as an FDA-grandfathered drug that can act as an electron donor in the mitochondrial electron transport chain at low doses, reducing reactive oxygen species; it crosses and accumulates behind the blood-brain barrier. In Alzheimer's trials, high doses showed no benefit while the low-dose 'control' arms (4–8 mg/day) appeared beneficial, pointing to a U-shaped dose response. Animal studies suggest neuroprotection and prevention of Alzheimer's, but she notes there is no human placebo-controlled prevention trial. She flags G6PD deficiency and serotonergic/psychiatric drug interactions as key cautions.
"Methylene blue is an interesting option for mitochondrial function and Alzheimer's prevention." She wants trials that better dial in low doses.From Methylene Blue and Mitochondrial Function
The evidence
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Human trial
A randomized trial in dementia patients found no benefit and worse outcomes at 200 mg/day, while the 8 mg/day control arm showed significant improvements in brain atrophy.
Read the study Discussed in Methylene Blue and Mitochondrial Function -
Human trial
A phase III trial in mild to moderate Alzheimer's found no benefit from 75 mg or 125 mg twice daily compared with a control group taking 4 mg twice daily.
Read the study Discussed in Methylene Blue and Mitochondrial Function -
Human trial
A revised analysis of the phase III trial data found the 4 mg twice-daily control dose may be beneficial, especially as add-on therapy with other Alzheimer's drugs.
Read the study Discussed in Methylene Blue and Mitochondrial Function -
Human trial
In adults aged 22–62 compared with a placebo (blue food coloring) group, a 280 mg dose increased MRI brain response during vigilance tasks and correct memory-test responses by 7%.
Read the study Discussed in Methylene Blue and Mitochondrial Function -
Animal
In animal studies of brain injury, methylene blue increased neuronal survival by inducing autophagy and decreasing cell death.
Read the study Discussed in Methylene Blue and Mitochondrial Function -
Animal
Multiple animal studies show preventive effects of methylene blue for Alzheimer's, but no human randomized placebo-controlled prevention trial has been done.
Read the study Discussed in Methylene Blue and Mitochondrial Function
Doses used in studies
Amounts reported in the research, not dosing recommendations.
| Dose | Context |
|---|---|
| 4 mg twice daily (8 mg/day) | Low-dose 'control' arm in Alzheimer's phase III trial that may have been beneficial |
| 75 mg or 125 mg twice daily | High-dose arms in phase III Alzheimer's trial, no benefit over 4 mg control |
| 200 mg/day vs 8 mg/day | Dementia RCT; authors concluded a trial with max 20–60 mg/day was needed |
| 8 and 16 mg/day | Completed clinical trial (NCT03446001) with results not yet posted |
| 280 mg (about 4 mg/kg) | Single-dose MRI and memory study in healthy adults |
| 0.5–4 mg/kg beneficial; above 10 mg/kg reduced response | Animal (rat) dose-response data; not directly translatable to humans |
Cautions
- People with G6PD deficiency are at risk of hemolysis; caution is warranted.
- At higher doses it may inhibit MAOA; case reports of serotonin syndrome with hospital IV use, and an FDA warning about interactions with psychiatric medications.
- Not appropriate for those on MAOIs.
- Higher doses turn urine green to blue; long-term high doses (as in malaria treatment) can tint skin and eye whites bluish.
- More is not better: at higher doses it can pull electrons from the electron transport chain, slightly reducing mitochondrial energy.
- Pet-store methylene blue isn't guaranteed pure; she suggests USP grade made for human consumption. It also stains surfaces.