A white shirt, once stained with yellow underarm blotches or splashes of tomato juice, usually meets one of two fates: a punishing chemical bath or a slow exile to the back of the closet. But scientists in Japan have found a surprisingly gentle alternative in the form of a beam of blue light.

It’s not just any light. At 445 nanometers, a visible wavelength near the indigo end of the spectrum, high-intensity blue LED light has shown remarkable stain-fighting powers, capable of degrading the compounds that cause yellowing without damaging even the most delicate of fabrics.

“We were surprised by how effective the process turned out to be,” said Dr. Tomohiro Sugahara, a materials scientist at Asahi Kasei Corporation and lead author of the study published in ACS Sustainable Chemistry & Engineering, as per New York Times. “Seeing it work so well on yellowing in actual dress shirts was especially striking.”

The Science of Stains and Why They Stick Around

Yellow stains are chemically stubborn. Most are caused by compounds in sweat and skin oils (like squalene and oleic acid) or by food pigments like beta-carotene and lycopene, found in oranges, tomatoes, and other colorful staples of the human diet. Either way, they’re really tricky to get out.

Traditional methods like bleach or ultraviolet light can break down these stains, but they come at a cost. Hydrogen peroxide can weaken fibers, and UV exposure can discolor or degrade fabrics. These treatments also require energy, solvents, or additional chemicals—all of which pose environmental challenges.

Sugahara and his colleague Hisanari Yoneda wanted to find a way around those issues. They had already shown that blue light could remove yellowing from plastics. Now, they wondered, could it do the same for textiles?

They started in the lab with vials of pure stain-causing compounds and hit them with blue LED light under normal atmospheric oxygen. Within three hours, the once-colorful compounds had faded. Molecular analysis showed that the light, in concert with oxygen, was breaking apart the double bonds in the molecules, turning them into colorless aldehydes and carboxylic acids.

“Our method utilizes visible blue light in combination with ambient oxygen, which acts as the oxidizing agent to drive the photobleaching process,” Dr. Sugahara explained. “This approach avoids the use of harsh chemical oxidants typically required in conventional bleaching methods, making it inherently more sustainable.”

But Does It Work on Shirts?

To test real-world stains, the researchers stained cotton swatches with squalene—the skin oil compound most responsible for underarm discoloration—and aged them with heat. They then exposed the swatches to three treatments: hydrogen peroxide, ultraviolet light, and blue LED light.

The blue light emerged as the clear winner. After just 10 minutes, it had removed more yellowing than either of the other methods—and without ruining the fabric. Even delicate materials like silk and polyester held up under the blue beam. No discoloration, no fraying.

The technique even worked on food-based stains like orange juice and tomato sauce—notorious offenders for anyone who’s worn a white blouse to lunch.

Just as notably, the method left other colors alone. Sugahara said that blue or black-and-white checkered fabrics remained unchanged after treatment. That hints at the method’s potential versatility for treating a variety of garments—not just white shirts.

“Traditional washing generates a lot of microplastics, and this method appears to minimize the use of mechanical forces and water to eliminate the stains” Dr. Hinestroza, a fiber scientist at Cornell University who was not involved in the study told New York Times.

He also emphasized the environmental benefit: gentler cleaning means clothes last longer, reducing textile waste—a major source of landfill mass and microplastic pollution.

Will You Be Able to Use It at Home?

The researchers emphasize this isn’t just shining a blue light. You need a specific lamp with specific wavelengths to get it to work, and it’s not yet been turned into a real-life product.

The research is still in early stages, and safety and colorfastness tests are ongoing. The authors, who are both employed by Asahi Kasei Corporation—a company known for textiles and electronics—believe that commercialization could be just a few years away.

The researchers say the technology could be ready for practical use within five years. According to Dr. Sugahara, early applications might include dry cleaners, bridal shops, or costume rental services. Eventually, the method could also be adapted for home appliances, though more testing is needed to ensure safety and colorfastness across a wider range of textiles.

As the world searches for cleaner, safer, and more sustainable consumer solutions, the idea of a light-powered laundry aid—one that doesn’t require bleach, heat, or plastic-heavy detergents—seems more science than fiction.