Intervention
Methylene Blue
Last updated Sat May 30 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
Pre-clinical— Strong mechanism, very limited human longevity data
What it is
Methylene blue (methylthioninium chloride) is a phenothiazine dye in clinical use since the late 1800s. It is a redox-cycling molecule that shuttles electrons in mitochondria, partially bypassing complex I/III dysfunction. It is also a potent monoamine-oxidase inhibitor.
Why interest
- Improves mitochondrial respiration in cell and animal models.
- Neuroprotective in Alzheimer's and ischaemic stroke rodent models.
- Cognitive enhancement in small human studies (low single doses, acute).
Significant cautions
- Serotonin syndrome: MB is a potent MAO-A inhibitor; combining with SSRIs, SNRIs, tramadol, triptans, MDMA, many supplements (St. John’s wort, 5-HTP) can cause fatal serotonin syndrome.
- G6PD deficiency: causes severe haemolysis.
- Pregnancy: contraindicated (teratogenic).
- Quality: industrial-grade methylene blue contains heavy metal contaminants; only pharmaceutical-grade or USP-grade is safe.
- Dose-response: hormetic; high doses become pro-oxidant.
Don't combine
If you take any SSRI/SNRI antidepressant, do not take methylene blue. This combination has killed people.
Related entries
Mitochondrial dysfunction, Cognitive decline, Alzheimer's disease.
References
- Tucker, D., Lu, Y. & Zhang, Q. From mitochondrial function to neuroprotection: an emerging role for methylene blue. Mol. Neurobiol. 55, 5137–5153 (2018).