Adding a tiny amount of methylene blue to heart cell power plants makes them use oxygen more efficiently, no matter what fuel they're burning.

A tiny amount of methylene blue helps heart cells make energy better, but too much actually hurts them — it’s a classic case of 'less is more'.

Methylene blue makes heart cell power plants produce more harmful molecules when using one fuel (glutamate/malate), but less when using another (succinate), showing its effect depends on what the cell is burning.

Adding methylene blue doesn’t change how well heart cell power plants can hold onto calcium, meaning it doesn’t protect against the pore that can cause cell death under stress.

Methylene blue helps brain cells use oxygen more efficiently to make energy after they’ve been starved.

In a lab test with mouse brain cells, a chemical called methylene blue makes the energy-producing parts of the cells work harder without using energy to make ATP, while another chemical called azure I doesn’t do anything. This suggests methylene blue might be messing with how the cells normally control their energy production.