What is Methylene Blue?
Methylene blue is the active ingredient (methylthioninium chloride) in research-grade USP material. It is one of the oldest synthetic compounds in pharmacology — first synthesized in 1876 by Heinrich Caro. The compound's redox-active phenothiazine core can shuttle electrons in cellular respiration, lending it both diagnostic (urine staining, antidote properties) and investigational metabolic uses.