Methylene blue helps liver cells in mice stay alive when they're damaged by certain drugs by giving them an alternate way to make energy, stopping harmful stress and cell death.

Methylene blue helps mitochondria, the energy factories in our cells, move electrons more smoothly so they don’t accidentally create harmful waste molecules called reactive oxygen species.

Scientists found that a blue dye called methylene blue can help fix a broken energy system in mouse brain cells, but a related chemical called azure I can't — meaning only the original dye can jump over a specific energy block.

Methylene blue acts as an alternative electron carrier in the mitochondrial respiratory chain, enhancing cellular ATP production and modulating monoaminergic neurotransmission to reduce fasting-induced metabolic stress and appetite.

A chemical called Azure I, which comes from methylene blue, doesn’t fix the energy power plants in mouse brain cells—even though it’s better at blocking certain brain enzymes. This means it might work in other ways, not by helping cells make energy.

In mice, methylene blue fixes energy problems only if they’re caused by a specific broken part (Complex I)—not if another part (Complex III) is broken. This is different from what was seen in guinea pigs.