“Methylene blue makes your brain sharper.”
Methylene blue has not been shown to make healthy brains sharper; one small study found a slight memory boost one hour after a single dose.
Methylene blue is a prescription drug, not a proven brain booster. The case for sharper thinking rests on one small single-dose study, and the drug can cause dangerous reactions with common antidepressants and pain medicines.
Before trying methylene blue, ask a pharmacist to check it against every medicine and supplement you take.
Safety note: The FDA-approved label carries a boxed warning: methylene blue can cause serious or fatal serotonin syndrome when combined with SSRI or SNRI antidepressants, MAOIs or opioids. It must not be used by people with G6PD deficiency, an inherited condition, because it can destroy red blood cells. Severe allergic reactions can also occur. The label also warns that it may harm an unborn baby and says to stop breastfeeding for up to 8 days after a dose.
Talk to a healthcare professional if: you are thinking about trying methylene blue and you are pregnant or breastfeeding, take an antidepressant, an opioid or another medicine that affects serotonin, or have G6PD deficiency.
The only direct test in healthy people is one small trial of a single dose, with a slight memory gain. Nothing shows that taking it regularly sharpens thinking, and a large trial of a related compound in Alzheimer's disease found no benefit.
Methylene blue has not been shown to make healthy brains sharper; one small study found a slight memory boost one hour after a single dose. In that 2016 trial, 26 healthy adults got either a low dose of methylene blue or a placebo; the methylene blue group had about 7% more correct answers on a short-term memory test, and brain scans showed more activity during attention and memory tasks. No trial has shown lasting gains from regular use.
Methylene blue is a blue dye and a prescription drug. The FDA has approved it as an IV treatment for methemoglobinemia, a blood disorder that keeps blood from carrying oxygen well. In Alzheimer's disease, a 15-month trial of 891 patients tested a related compound, LMTM, and found no benefit on memory, thinking or daily function at either dose; the drug's maker paid for the trial. Much of the excitement about brain effects comes from animal studies and brain scans rather than measured gains in daily thinking.
- Rodriguez P, Zhou W, Barrett DW, Altmeyer W, Gutierrez JE, Li J, Lancaster JL, Gonzalez-Lima F, Duong TQ. Multimodal Randomized Functional MR Imaging of the Effects of Methylene Blue in the Human Brain. Radiology. 2016;281(2):516-526. DOI: 10.1148/radiol.2016152893. PMID: 27351678
- Gauthier S, Feldman HH, Schneider LS, Wilcock GK, Frisoni GB, et al. Efficacy and safety of tau-aggregation inhibitor therapy in patients with mild or moderate Alzheimer's disease: a randomised, controlled, double-blind, parallel-arm, phase 3 trial. Lancet. 2016;388(10062):2873-2884. DOI: 10.1016/S0140-6736(16)31275-2. PMID: 27863809
- American Regent. PROVAYBLUE (methylene blue) injection, for intravenous use: US prescribing information. Revised 2/2024. DailyMed