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When I bought my first pair of Merino wool underwear—a pair of Ibex briefs—from a Vermont gear shop in 2017, it was a game changer. I dubbed them my “adventure undies,” since they were the first pair I’d reach for when packing for every type of outing. On long hikes, multiweek canoe camping trips, and snowy mountain excursions, they beat out my other undergarments in every category: comfort, breathability, and a feeling of relative cleanliness I crave when crawling into my sleeping bag at night. Since then, I’ve grown my fleet of wool pairs, and they are my favorites across the board.
Turns out, I’m not the only member of the Merino-panty-superfandom. I found that most of my male hiking buddies don’t put too much thought into this small gear choice, and don’t mind wearing the same pair for days on end. But for women, the right choice of undergarment can make or break a backpacking trip. Moisture trapping, chafing, and excessive odor are veritable hike ruiners that can sometimes escalate to UTIs or yeast infections. Plus, packing a clean pair for every day of your hike isn’t always an option on long treks. Merino underwear can solve many of these problems.
Dr. Lillia Loriz, a professor of nursing at Brooks College of Health at the University of North Florida and accomplished long-distance hiker, agrees.
“Unlike synthetic materials that trap sweat and odor, Merino wool naturally wicks moisture away and has antimicrobial properties that keep bacteria in check,” she says.
And Loriz is no stranger to long stretches on trail: She’s hiked a 750-section of the Appalachian Trail, 1,300 miles on the Pacific Crest Trail, 600 miles on the Florida Trail, the entire Colorado Trail, and others.
Loriz says that Merino wicks moisture better than cotton, and while some synthetics have antimicrobial capabilities, this is where Merino wool shines. While your synthetic undies might pick up stink after a day or two on the trail, Merino wool pairs tend to feel and smell fresh for longer.
In addition to choosing the right pair of underwear for hiking, there are steps hikers can take to feel clean and comfortable on trail and in camp. Loriz recommends always packing a second pair of underwear on a long backpacking trip.
“Switch between pairs to allow for drying. Wash when water source allows,” she says. “Some [hikers] also wear them right-side-in then inside out. However, switching between pairs to assure clean and dry use is best.”
If sweaty underwear does cause chafing, Loriz recommends using a skin barrier like Body Glide, Burt’s Bees Hand Salve, or Udder Butter.