So, why is pee yellow? Have you ever wondered why? If you have ever wondered but got no answers, there is good news for you, as scientists have finally found out why your pee is yellow.

In a recent study that was published on January 3 in Nature Microbiology, researchers have for the first time discovered the enzyme that gives urine its golden color.

Why Is Pee Yellow: Scientists Have The Answers

The reason why urine appears yellow has now been explained by the discovery of an enzyme called bilirubin reductase, according to main author Brantley Hall, PhD, an assistant professor at the University of Maryland in College Park’s Department of Cell Biology and Molecular Genetics.

The study results may do more than answer an age-old question. “Although more research is needed, this finding could lead to improved treatments for jaundice and inflammatory bowel disease,” says Dr. Hall.

The goal of Hall and his group was not to truly determine the cause of yellow urine.

“Our lab studies gut microbes; we’re interested in understanding the functions these microbes perform and how that relates to human health,” Hall says.

Researchers looked at the potential connection between jaundice in infants and the billions of bacteria that live in our digestive tracts, or the gut microbiome.

Many babies have jaundice, which is a yellow tint to their skin that results from an accumulation of the yellow chemical bilirubin in the infant’s blood. Babies’ livers aren’t mature enough to eliminate bilirubin, which is why this occurs.

Why is Pee Yellow? Bilirubin Reductase Is the Enzyme That Causes Pee to Be Yellow

Scientists have known for more than a century that the body converts blood bilirubin into urobilin molecules, which give urine its yellow hue. However, scientists were unsure exactly which gut enzyme, or group of enzymes, was in charge of this change.

Hall and his colleagues found that bilirubin reductase, which is produced by gut microorganisms, transforms bilirubin into urobilinogen, a colorless byproduct.

“Urobilinogen then spontaneously degrades [breaks down] into urobilin, which is responsible for the yellow color,” Hall says.

It’s Unlikely That Dehydrated People Produce More Bilirubin

Why Is Pee Yellow? Scientists Have Finally Found Out
Why is pee yellow? Image: iStock

Urine color is frequently used to determine one’s state of hydration; a deeper yellow tint indicates possible dehydration.

“People ask me if there is more bilirubin produced when you’re dehydrated, and we don’t think that’s the answer. We think there’s basically a constant amount of bilirubin produced by gut microbes, and the color that you see is a factor of hydration,” says Hall.

According to the Cleveland Clinic, urine color varies naturally from day to day but should generally remain within a certain spectrum of yellow. Experts say that pee that is light straw or amber is excellent and indicates that you are sufficiently hydrated.


Hi, I am David! I am a student at the African University College of Communications where I pursue a degree in Strategic Communications. I started my own blog because I'm passionate about motivation, mental health, and healthy living, and I want to help others live healthy lifestyles by sharing my knowledge and experiences. My main areas of interest are motivation, mental health, and general healthy living. I attempt to inform and motivate my readers to make healthy decisions that are right for them because I feel that a balanced approach to fitness and health is essential for long-term success. My goal is to enable others to take charge of their health and lead fulfilling lives. I want to help my readers reach their health and fitness objectives through my blog by offering useful advice, research with solid supporting data, and inspirational material. Website: Contact Info: For collaborations, partnerships, or general inquiries, please email me at Also, contact me on WhatsApp at +233554389888.

Write A Comment