hen we tested tees for our story on the best-sweat wicking running shirts this year, one material continued to pop up: Celliant, a technology that’s pretty new to the scene and claims to improve blood flow. You may have seen it on the labels of sheets at Target, but it’s beginning to move beyond the home furnishing space and into fitness apparel and outdoor climbing gear. It’s also FDA-Approved as a medical device, which is pretty unusual.

Hologenix, LLC, is the creator of Celliant, and they’ve heavily tested it — enough for the U.S. Food and Drug Administration to classify products containing Celliant as “wellness products.” It’s rare for a material to achieve this status, especially given that it’s not something you ingest, but rather something you wear. It was approved back in July of 2017, and at that point was in Salewa jackets, Tecnica ski boots, Xcel full wetsuits and Lumen sheets; a pretty wide variety of products.

Celliant is an insulation performance booster. “It’s a revolutionary patented technology that harnesses and recycles the body’s natural energy through the medium of fibers,” Topher Gaylord, senior vice president and general manager of the run, train and outdoor divisions of Under Armour says. The Celliant site explains it as “a proprietary mineral matrix that can be embedded into the core of a yarn or applied to a wide variety of fabrics.” Your body produces a certain amount of heat, eight to 15 microns of infrared light. And that can be harnessed (as it is in 37.5 fabric) to work for your body instead of just floating out into the air as unused energy. When your body heat is recycled, it can be reflected back to you as infrared light, which is then absorbed by the body.

An Under Armour top with Celliant.

Before Celliant becomes a material, it’s a thermo-reactive material that’s melted into a resin and then loaded into the core of recycled fibers (which in turn helps to increase microcirculation and peripheral blood flow, according to Salewa). “Because the Celliant minerals are melted into the polyester, they can never wear off, wash out, or decay,” Mark McCarthy, senior project manager at Salewa, says.

In addition to Salewa and Under Armour, Olivers Apparel and Rhone both use Celliant in technical and recovery clothing. In Salewa alone, it’s in 21 different pieces in the alpine mountaineering, trekking and lifestyle apparel. Olivers Apparel has worked with Celliant for the past six months, David Wolfe, founder of Olivers says. “We loved the benefits of the technology and loved the way our mill in Peru was able to utilize it in conjunction with their Pima cotton.”

We’ve yet to put Celliant through a thorough long-term test, but it’s clear that big names are buying-in, and that it’s certainly more than snake oil.

Gear with Celliant

Tecnica Alpine Mach Sport 120 EHV Ski Boots 2019

Tecnica has long been heralded in the ski boot market for its impressive and structured footings. The Tecnica Alpine Mach features an extra high volume footbed and Celliant in the walls of the boot to ensure warmth.

Olivers Apparel Club Tee

The Celliant cotton jersey will quickly become a staple in your off-duty wardrobe. It claims to recycle your body energy, increase circulation and thermoregulate your body temperature. Pick one up in navy, black or white.

Under Armour Athlete Recovery Sleepwear

These joggers are just one piece of the recovery system Under Armour built. The sweats are cool to the touch, stretchy and work just as well sleeping in a tent as they do in your own bed.

Salewa Pedroc Hybrid Alpha 2/1 Jacket

This nylon windbreaker is breathable, strong, lightweight and packable.

Everything You Need to Know about 37.5

Looking to get faster and stronger? It’s time to upgrade your workout gear with this performance-enhancing material. Read the Story