People generate a staggering amount of hair waste—salons in the U.S. and Canada toss out some 31.5 tons a day. But what if that discarded hair didn’t have to be waste?
Nanako Hama gets a lot of mail. Mostly from strangers who live in her home city of Tokyo, but many packages also arrive from further afield in Japan. In lightly padded envelopes, they send locks of their hair—long, short, dyed, relaxed, permed—hoping to recycle it.
People generate a staggering amount of hair waste—salons in the U.S. and Canada toss out some 31.5 tons a day, and that figure is sevenfold higher in Europe. Nearly all of that waste ends up in landfills and incinerators, where it can release harmful greenhouse gases that contribute to climate change.
But hair, proponents say, possesses so many useful properties that it’s a shame to simply toss it out. Which is why people all around the world, like Hama, have been collecting hair and finding innovative ways to recycle it, from weaving it into mats for mopping up oil spills to liquidizing it for use as a fertilizer.
“When you have hair on your head, it’s really important. But when it falls or you cut it, it suddenly becomes garbage,” says Hama. “Hair can be transformed into something really valuable.”
A MAGNET FOR OIL
Hama is part of the San Francisco-headquartered nonprofit Matter of Trust (MoT). Members work at more than 60 hubs dotted across 17 countries, using machines to felt hair donated from local salons and individuals into inch-thick square mats roughly 33 inches across. The mats are then used to clean up oil slicks.
Hair is particularly well-suited for this, says MoT cofounder Lisa Gautier. “That’s because its rough sort of scaly outer layer lets oil cling to it.”
More specifically, hair is made of 95 percent keratin, and it’s this fibrous protein that mediates hydrophobic interactions—in other words, “oily stuff sticking together,” says Glenn Johnson, a materials scientist with the U.S. Air Force, who works with MoT to help develop and test the mats.
“Plus, hair has a large surface area,” says Megan Murray, an environmental scientist at the University of Technology Sydney, in Australia. In a 2018 study, Murray found that buffers made of recycled human hair could adsorb 0.84 grams of crude oil onto its surface for every gram of hair—significantly more than polypropylene, a type of plastic that’s typically used to clean up oil slicks.
MoT’s mats have been used in major oil spills, including the 2010 Deepwater Horizon and 2007 Cosco Busan incidents. Later this year, Hama’s team will deploy their mats in Niigata City, some four hours north of Tokyo, where more than 300 leaky wells remain in an abandoned oil field that once boasted the country’s largest oil production.
The Air Force, on the other hand, uses hair mats to clean up water that gets contaminated with liquid fuels and foam following firefighting training.
“In addition to oily surfactants, foam also sticks to hair,” says Johnson. Testing is ongoing, but he says the mats “show promise” of being deployed at an operational scale cleaning up the more than two million liters of dirty water produced by this training every year.
Recycled hair also has more common everyday applications—in buffers placed around drains to prevent motor oil from polluting stormwater runoff—and by extension, water bodies— as well as biodegradable grease traps to soak up cooking oil. Hama’s mats, for instance, will be used to filter wastewater next month at Japan’s biggest outdoor music event, the Fuji Rock Festival.
A HELPING HAND FOR PLANTS
Recycled hair is also useful as fertilizer and mulch material.
“Hair contains a lot of protein, which has a relatively high nitrogen content,” explains Stuart Weiss, a conservation ecologist at Creekside Science, an independent laboratory in California.
Nitrogen is crucial for plant growth, and each strand of hair is made of roughly 16 percent of this essential nutrient. By contrast, a pile of cow manure typically has between 0.6 to three percent nitrogen.
Hair also releases nutrients more slowly than the equivalent amount of commercial fertilizer, which is important for preventing excess nitrogen from leaching into waterways, says Weiss.
A series of experiments conducted in the early 2000s demonstrated that uncomposted hair was useful for growing herbs such as basil, sage, and peppermint; horticultural crops like lettuce; as well as marigold, foxglove, and other ornamental plants.
More recently, entrepreneur David Denis has found success with his startup, CutOff Recycle, which sold more than 560 gallons of liquid fertilizer made from human hair to farmers northern Tanzania last year.
The feedback from the farmers, who mainly grow tomatoes and leafy vegetables like spinach and amaranth, has been very encouraging, says Denis, who cofounded the firm in 2020.
“The weight of their tomatoes has increased by 25 percent, and the increased yield is very visible from the larger leaves of the leafy vegetables,” he says.
Agriculture experiments halfway across the world—in Chile’s Atacama Desert, the driest place on the planet—have yielded similarly promising results. Last year, MoT worked with local farmers to see if hair could help reduce water lost as it evaporates from olive, avocado, and lemon trees.
“If you use our hair mats on top of the soil, you use 48 percent less water,” says MoT’s Chile head Mattia Carenini of the study findings.
The hair mulch also helped increase nitrogen, improve soil health, and boosted fruit yield by 32 percent.
SOWING SEEDS OF HOPE
Recycled hair is also playing a role in restoring degraded land and seascapes. The Scottish-based charity Seawilding, for instance, is currently trialing hair as a medium for sowing seagrass. The U.K. is estimated to have lost 44 percent of its seagrass meadows—a vital marine habitat and massive carbon sink—since 1936.
On land, recycled hair is being applied in the grasslands of the Presidio, a national park overlooking San Francisco’s Golden Gate Bridge. In the past year, Weiss has helped MoT seed purple needlegrass (Stipa pulchra) and meadow barley (Hordeum brachyantherum) under felted hair balls on compacted soil that was once a parking lot.
Although currently only midway through the experiment, the results “are just spectacular,” he says. “You look at it and can totally tell which box had the hair treatment.” On average, native grass cover in plots with hair was 75 percent full versus under 10 percent in the control plots containing straw.
“It’s just a great way to use hair in a productive way,” says Weiss. But he cautions that further testing is needed to figure out how to scale experiments.
Gautier, however, firmly believes that our crowning glories don’t have to lose their luster once they’re lopped off our heads.
“Hair is an answer literally hanging in front of our eyes—for oil, soil, and seas,” she says.
