Critics Sound Off on Xenon

Furtenbach first spoke to Outside in December 2024, and predicted that his idea would likely ruffle feathers in the small world of Everest guides.

“I know there is going to be criticism,” he said. “People will say it’s doping. People will say it’s not real mountaineering anymore.”

The pushback was even harsher and more substantial than he predicted. On January 22, the International Climbing and Mountaineering Federation released a statement condemning the use of xenon. The statement called into question the science behind xenon’s use for acclimatization, and also pointed out the ethical dilemma of using a substance that’s banned by WADA. “Acclimatization to altitude is a complex process that affects the various organs/systems such as the brain, lungs, heart, kidneys and blood to different degrees, and is not fully understood,” the statement read. “Since the physiological changes take days to weeks to influence the organism, from a physiological point of view, a single, one-off drug cannot be the key to improved acclimatization or increased performance.”

But not everyone in the climbing world is as critical. In an interview with Austrian news site Der Standard, mountaineering legend Reinhold Messner, the first person to climb Everest without supplemental oxygen, called the method “fantastic.”

“I think it’s brilliant of Furtenbach to have realized what xenon can do for high-altitude mountaineering,” Messner said. “I congratulate him on his success.”

Furtenbach shrugged off the ethical questions over using the substance. WADA rules do not apply to mountaineering, and clients and guides already use a wide array of substances to artificially enhance their performance on the mountain, most notably bottled oxygen. Some mountaineers also bring an anti-inflammatory steroid called dexamethasone—or DEX—on expeditions to mitigate symptoms of altitude sickness.

Furtenbach claims xenon isn’t doping, but rather a protective measure similar to bottled oxygen.

“We are paid to be responsible and to care about the lives of our clients,” he said. “We have to do everything we can to make the climb as safe as possible. And if using oxygen or other gasses makes the client safer, then that’s what we will do.”

Still, the climbing federation wasn’t the only body to criticize Furtenbach’s use of xenon. Throughout January, other Everest guides also chimed in with pushback on the new method. New Zealand guide Guy Cotter told Outside that he viewed ascents using xenon to be “no more than a stunt.”

“My feeling about this new proposal to use xenon to dope up for Everest is ‘why all the rush?’” Cotter told Outside in an email. “An ascent of Mount Everest, when done properly, is one of the most amazing adventures on earth.”

British guide Kenton Cool told The Financial Times that, while he respected Furtenbach, he would not recommend the method to his clients. “Maybe it’s a reflection on modern-day society, where we want everything yesterday, and nobody’s willing to wait,” he said.

American guide Garrett Madison echoed that sentiment. Madison also offers rapid guided ascents on other peaks. But he said that the traditional six-week tour to Everest offers much more to climbers than just a moment spent on the summit.

“The tried-and-true ascent is a spiritual journey,” Madison told Outside. “You soak up the culture of Nepal and the culture of the Sherpa people and you get to really know this amazing environment. I wish expeditions could last longer.”

Madison said the week-long trip is just the next step in Everest’s evolution as a bucket-list travel destination. “Why not just fly up there in a helicopter and touch the top so you said you did it?” he says.

Furtenbach pushed back against the criticism in a series of emails with Outside: “For those with the time and flexibility to spend eight or ten weeks on an expedition, I congratulate them on the opportunity to immerse themselves in a new culture and environment at their own pace,” he wrote. Furtenbach Adventures also offers the traditional eight-week trip to Everest, as well as the three and now one-week tours, he pointed out.

“Everyone should be free to choose their expedition style and duration, with tolerance for differing approaches, provided no one else is harmed or endangered,” he added.

But there are lingering questions about whether or not rapid trips up Everest increase the risk. Guides who spoke to Outside stressed that patience on Everest is often a virtue, especially in years when the weather presents challenges. These days, hundreds of climbers surge onto the mountain at the same time to make the most of narrow windows of good weather. Climbers on traditional eight-week ascents can wait out the crowds.

Guides also said that acclimatization hikes on Everest give a client “mountain sense,” which can come in handy during an emergency. “There’s a lot to be gained by going onto the mountain in terms of overall preparedness,” Madison said. “You adapt to the cold and the wind. You learn the route. You get a sense of where you are on the mountain.”

Experts also expressed concern that climbers on rapid ascents may have a lower chance of survival if they were to lose access to bottled oxygen above 26,000 feet—the so-called “death zone.” At that altitude, climbers no longer breathe in enough oxygen to stay alive.

“A climber that’s been on Everest for six weeks and has done multiple rotations to Camp II or Camp IiI—if their oxygen runs out, they will be in trouble but they won’t die as quickly,” Dr. Hackett said.

Furtenbach disagreed and argued that at-home acclimatization is just as good as doing so on a mountain. Furtenbach said his clients will be hooked up to oxygen “as soon as it makes sense,” and that the four climbers on the one-week expedition would have a one-to-one or two-to-one guide-to-climber ratio. This high ratio, he says, will ensure that clients always have access to oxygen, and have the help they need in case of an emergency.

And Furtebach also pushed back on fears that Everest’s route will someday be clogged with climbers who are on rapid ascents. The expensive trips, he says, will always cater to a small number of climbers.

“The one-week expedition will always be a niche offering,” he wrote in an email. “It is decidedly not suitable for everyone and requires such extensive preparation, logistics, and financial resources that it could never become a mass-market product.”