Wool seems to be the ideal fabric for runners when it comes to keeping warm, drying quickly and resisting odor, so we figured our undergarments should include some wool as well. We tested a handful of underwear options, and the following have become our top picks when running and staying active this winter.
Ibex Women’s Natural Brief ($35)
The shortest inseam option here, Ibex’s Natural Brief uses the company’s lightest weight Pro-Tech Lite fabric, consisting of 83% merino wool, plus 12% nylon and 5% elastane for added durability and a close-to-skin fit. A low-rise anti-slide waistband sits fairly low, to the point where Ibex recommends sizing up one size from your usual for the best fit. Soft elastic at the leg openings keep the briefs in place without riding up, and forward seams on the hips are dependably chafe-free. Their relatively high merino content makes them among the most effective briefs we tested for odor control and reusability.
Tracksmith’s Brighton Briefs provide broader coverage on all sides, with a mid-rise profile, taller inseams, and more material across the back. These briefs have a wool content of 66%, plus 32% nylon and 2% elastane to create a secure fit along with a midrise knit rib waistband. Open stitching throughout the briefs creates a soft feel and optimizes breathability, and seamless construction eliminates chafing. These are our preference for speed workouts or other high demand activities where we need full range of motion without any shifting.
Woolx Lila Boy Shorts ($36)
This full coverage short is ideal for those looking for underwear that’s a bit warmer and won’t shift around on the run. We’re a fan of boy shorts because the style promises a very slim chance of chafing or unexpected bunching. The Woolx Lila is soft and light, with 85% merino wool, 12% nylon and 3% spandex, and includes a wide waistband that holds up well under shorts or running tights. Even with side seams that are a bit awkward in the front above the thigh, these briefs offered a comfortable fit when tested throughout our winter runs. They dried quicker than cotton bikini briefs and kept odors at bay. The Lila comes in two color options, and we’ll definitely be adding more boy shorts to our underwear drawer.
Branwyn Essential Bikini ($36)
The bikini by Branwyn became a staple in our underwear line-up as a simple, seamless and durable option on any run. The fabric is a knit blend of 81% extra fine merino wool, 12% nylon and 7% Spandex, and stays in place during faster short runs as well as on longer slow mileage days. While it’s not the softest wool underwear we tested, the bikini is dependable as a brief that goes unnoticed during a run and dries quickly after. The four-way knit stretch has a snug fit and doesn’t hold odor after consecutive washes. This style was one we tested that fit more comfortably and remained invisible under skin-tight shorts and running pants.
Men: Smartwool Intraknit Boxer Brief ($50)
Our biggest issue with boxer briefs is their tendency to slide upwards and bunch up during activity, but this has not been an issue at all in our testing of these Smartwool briefs with a 6” inseam. Fabric construction of 35% merino wool, 35% tencel, and 22% polyester combines with 8% elastane to ensure that they cling to your upper legs without sliding, and the fabric itself has excellent softness and odor control from the merino and tencel combination. Zoned mesh ventilation helps with moisture management and thermoregulation in higher sweat areas, but the material is thick enough to provide strong insulation on cold winter outings.