Does methylene blue actually improve energy and brain function in healthy people, or are the benefits mostly theoretical?

There is some human evidence, but it is much narrower than the online claims. A randomized study of 26 healthy adults tested a single oral administration of methylene blue and reported changes in brain activity during attention and memory tasks, alongside improved memory retrieval. That is a useful signal for further research. It does not establish that daily use improves work performance, chronic fatigue, exercise capacity or long-term brain health. A brain scan changing is also not automatically evidence that someone functions better in everyday life.[1]

The interest comes partly from methylene blue’s effects on cellular oxidation-reduction processes and mitochondrial energy handling. A plausible mechanism cannot tell us who benefits, how long an effect lasts or whether repeated exposure is worthwhile. The practical conclusion is that routine “energy optimization” claims run ahead of the healthy-human outcome evidence. Methylene blue is also an active drug with serious interaction and hemolysis warnings, rather than a harmless food coloring; a small efficacy experiment cannot establish safety for unrestricted use.[1][2]