Methylene Blue (MB) is a phenothiazine derivative and redox-active compound widely used in biochemical and cellular research. It functions as an electron carrier and redox indicator, capable of cycling between oxidized (blue) and reduced (leucomethylene blue) forms. This reversible redox behavior has made it a valuable research agent for studying mitochondrial respiration, oxidative stress, and cellular energy metabolism.

In experimental models, Methylene Blue has been used to explore its ability to influence mitochondrial electron transport, modulate nitric oxide signaling, and act as a redox mediator in neuroprotective and metabolic pathways. Due to its well-characterized pharmacokinetics it serves as a model compound in studies investigating absorption, first-pass metabolism, and dose-response dynamics.