Some of the most powerful tools in modern medicine are not new. They are old molecules whose original applications have been overshadowed by their current ones — compounds that have been sitting in the medical literature for decades, waiting for the science to catch up to what they actually do. Methylene blue is one of the most striking examples. The compound was first synthesized in 1876. It was used as a textile dye, then as one of the earliest pharmaceutical antimicrobials, then as the first synthetic medication ever administered to humans. For over a century, it was used in clinical medicine for treating methemoglobinemia, certain infections, and various other conditions. But methylene blue's most interesting properties — its effects on mitochondria, cognition, and neuroprotection — have only come into clinical focus in recent decades. And those effects make it one of the most valuable tools in modern longevity and cognitive optimization medicine. At AgeRejuvenation's Wesley Chapel, South Tampa, Brandon, Winter Park Orlando, and Winter Garden Orlando locations, methylene blue is integrated into protocols for cognitive enhancement, mitochondrial support, and longevity strategy — particularly for patients dealing with cognitive symptoms, mitochondrial dysfunction, or chronic fatigue.