Main mechanism of action of Methylene blue involves inhibition of nitric oxide synthase and guanylate cyclase. In Alzheimer: a mechanistic study found that methylene blue oxidizes cysteine sulfhydryl groups on tau to keep tau monomeric. One preclinical treatment study in tauopathy mice reported anti-inflammatory or neuroprotective effects mediated by the Nrf2/antioxidant response element (ARE); another reported insoluble tau reduction and a learning and memory benefit when given early. In Methemoglobinemia: Methylene Blue acts by reacting within RBC to form leukomethylene blue, which is a reducing agent of oxidized hemoglobin converting the ferric ion (fe+++) back to its oxygen carrying ferrous state(fe++). As antimalarial agent: Methylene Blue, a specific inhibitor of P.falciparum glutathione reductase has the potential to reverse CQ resistance and it hinders the polymerization of haem into haemozoin similar to 4-amino-quinoline antimalarials. For ifofosamide induced neurotoxicity: Methylene blue acts as an alternative electron acceptor, and reverses the NADH inhibition of hepatic gluconeogenesis while also inhibiting the transformation of chloroethylamine into Chloroacetaldehyde, and also inhibits multiple amine oxidase activities, hindering the formation of Chloroacetaldehyde.[3] Methylene blue (MB) is readily absorbed in blood and quickly distributed to various organs. Other functions of MB include cognition enhancing properties and increase oxygen consumption efficacy in isolated mitochondria. MB (1 mg/kg) has also reported to increase COX activity and thereby improving energy functions in AD brains. MB acts as both mitochondrial restorer as well as antioxidant.[4]