July 14, 2025

Angelynn Tran 

11th Grade

Fountain Valley High School

Yes, methylene blue can turn your pee blue. And no, it doesn’t mean you’re a Smurf. So, what is this mystery substance? Methylene blue (MB) is a strong chemical dye used in medicine and biology. Historically, MB was first synthesized by German chemist Heinrich Caro in 1876 as a textile dye; however, scientists soon found out that this substance could be used to treat and diagnose certain diseases, such as malaria. Over the years, Methylene blue has become well integrated in medical diagnostics, treatment, and research– let's explore them!

Okay, so why does this substance turn your urine blue? There’s actually a practical use for this: diagnosing kidney health. Because methylene blue is such a strong dye, it’s easy to leave its visible traces as it moves through the body. This factor caught the attention of medical professionals and led to its use as a diagnostic tool for evaluating proper kidney function. If you peed blue after ingestion, it meant your kidneys were filtering properly and there were no blockages in your urinary tract. 

Beyond its use for visual diagnostics, methylene blue’s chemical properties support many cellular functions in our body, such as mitochondrial systems and oxygen delivery. Methylene blue is a redox dye, meaning that it can easily gain and lose electrons. Because of this property, MB can interact with our cells' mitochondria, a part of the cell responsible for producing ATP, a molecule that powers nearly all cellular energy.  Inside mitochondria, a process called the electron transport chain moves electrons across the inner membrane to generate ATP. Within this process, electron carriers support the process by moving electrons from one complex to another, which supports a concentration gradient needed to generate ATP. MB's role as a supporting molecule directs electrons through complexes in the electron transport chain, which is very beneficial to the cell, especially when mitochondrial functions aren’t working well. Scientists use MB to study Alzheimer’s and Parkinson’s by exploring how improving mitochondrial function in brain cells might slow or reduce disease progression. In addition to mitochondrial support, MB can also be used to treat methemoglobinemia–  a condition where hemoglobin in red blood cells is unable to carry oxygen properly. This leads to bluish skin (yes, the Smurf theme continues), fatigue, and, in severe cases, organ dysfunction. During treatment, MB acts as an electron donor, giving electrons to methemoglobin and converting it back to normal hemoglobin that can properly carry oxygen. 

From diagnosing kidney dysfunction to its ability to carry and receive electrons in the body, methylene blue is a “super dye” that has become incredibly useful in science and medicine. Its ability to treat conditions like methemoglobinemia and degenerative diseases such as Alzheimer’s and Parkinson’s shows how a molecule can have such vast effects in medicine and how much more we still have to discover!