JAnyone who has ever done sports outdoors in cold temperatures knows the onion principle: you wear several thin layers of clothing on top of each other so that you don’t sweat too much when you exert yourself, but at the same time you don’t freeze during longer outdoor adventures. The bottom layer is most important because it should fit tightly to wick moisture away from the skin. Wool is often chosen for this as it is odorless and keeps you warm even when it is damp. But even the particularly soft Merino wool has disadvantages: Some people find it scratchy and itchy. And sometimes you can get too warm in Merino ski underwear, which in turn affects your performance. In short: everything is not that easy.

Now the Swiss sportswear manufacturer “The combination of visionary technologies and innovative materials, implemented with intelligent functional zones, inspire athletes to achieve top performance,” says the manufacturer’s marketing language. Partial compression and thermoregulation technology would optimally adapt to the requirements of demanding top athletes and ambitious sports enthusiasts. They claim to have registered more than 800 patents for it. “Complex 3D structures of air ducts” would cool when you sweat and warm when you are cold. But can underwear deliver on such promises?