Lifeboat Foundation

Until now, scientists somehow didn’t know exactly what made pee yellow.

But that just may have finally changed. In a new study published in the journal Nature Microbiology, a multidisciplinary group of scientists out of the University of Maryland reported on their findings about a middleman enzyme called bilirubin reductase, which had long evaded researchers as they tried to figure out which precise compounds resulted in urine’s distinct yellow hue.

To be clear, as Healthline reports, scientists had known for more than 125 years that on a high level, urine gets its color from the disposal of old red blood cells as they degrade in our livers.