What is Methylene Blue?
Methylene blue is a chemical compound, not a peptide. A prescription injectable product is approved for acquired methemoglobinemia, a blood disorder. That approval does not establish a role for routine cognitive enhancement or general wellness.
Why people ask about it
Small human studies have explored attention, memory tasks, and brain activity. This early research does not establish lasting cognitive benefits or show that routine wellness use is safe or effective.
Evidence & important considerations
Methylene blue can interact dangerously with serotonergic medicines, including many antidepressants, and some opioids, potentially causing serotonin syndrome. The approved product is contraindicated in G6PD deficiency because of hemolytic-anemia risk. Review every medication and supplement with a qualified clinician; never use industrial or aquarium products for personal treatment.
Sources & further reading
Information reviewed September 16, 2026.