Furtenbach with the team during the record-breaking trip. Photo: Lukas Furtenbach//Instagram
The mountaineering world was paying close attention as an expedition of four British climbers recently attempted a record speed summit of Everest. Their goal: to travel from London to the top of Mount Everest and back in a week. But the spotlight was not due to what they were doing, but how they were doing it. Each climber took doses of xenon gas, an experimental substance with a limited track record in high-altitude mountaineering that proponents say can stave off the effects of altitude sickness.
Six-and-a-half days later, still with a half-day to spare, the expedition of former special forces members safely returned to the U.K. The previous record for this round-trip journey was 21 days. Their success has caused a buzz in the mountaineering world. Guiding companies are clamoring to learn about using xenon gas to prepare for low-oxygen environments.
According to Lukas Furtenbach, the founder of Furtenbach Adventures, the guiding company under which the British expedition scaled Everest, the interest in xenon gas has surged in the past weeks.
“Almost all major (Everest expedition) operators reached out and are interested,” Furtenbach told The Inertia regarding xenon gas. “Also, big organizations from China and India.”
The use of xenon gas at high altitude is still in the experimental phase. Furtenbach himself is one of the 15 or so climbers who had previously tested the gas on expeditions, including on Everest. Now, the success of the British climbers is one more case study in favor of its effectiveness.
The British expedition paid a visit to a doctor in Limburg, Germany, Michael Fries, who administered a “sub-anesthetic concentration” of xenon gas two weeks before the expedition. The gas, which has been used in larger doses as a form of anesthesia, has shown promising results to elevate the body’s production of erythropoietin, a protein that increases red blood cells and hemoglobin. On paper, it could mitigate the effects of altitude sickness.
In the case of the recent British expedition, the climbers supplemented the xenon gas dose by acclimatizing in hypoxic tents that mimic the low-oxygen environment of the Himalayas ahead of their departure. But Furtenbach says they’ve also done xenon-only climbs without the use of the hypoxic chambers that have isolated its effectiveness.
“For the (British) clients, we wanted double safety, so we applied both (xenon gas and hypoxic chambers),” said Furtenbach. “We know that xenon gas (played a big factor in the expedition’s success) because we have been testing a lot with xenon-only acclimatization as well.”
“Xenon has been used in anesthesia for more than 75 years and is very well researched,” he added. “There are no negative side effects known in anesthesia. The dosage we use for mountaineering is only a fraction of that used in anesthesia.”
Other experts are more skeptical about the gas’s efficacy. The New York Times’ coverage quoted a professor of cellular cardiology at King’s College London, Mike Shattock, who said, “Xenon probably does very little and there is virtually no reputable scientific evidence that it makes any difference.”
The International Climbing and Mountaineering Federation has already warned against using the gas, citing a lack of evidence and the dangers of inappropriate use.
Others are not worried about the gas’s effectiveness, but the ramifications it could have on the Nepalese tourism industry. Himal Gautam, the director of Nepal’s tourism department, has cautioned that faster summits of Everest would lead to less work for Sherpas.
Furtenbach disagrees, pointing out that his Sherpa salaries would remain unchanged and, on the other hand, the human impact on the mountain would be reduced.
“The opposite would be the case, as more climbers could come in the same period of time,” countered Furtenbach. “We need to pay our local staff for the full season, no matter how long a climber stays. So their job becomes easier while conserving the same salary. The reduction in garbage, resources, and human waste would also be significant.”
An Everest expedition via the traditional acclimatization strategy – done gradually on the mountain – takes six to eight weeks. In 2026, Furtenbach Adventures will offer two-week expeditions that include xenon gas doses before arrival. Furtenbach says the shortened xenon expeditions will be more expensive because of more complicated logistics.
As Furtenbach sees it, there will always be a place for purists who prefer to hike without the aid of oxygen or xenon. But he claims that in the not-too-distant future, the use of xenon gas will be more commonplace, making mountaineering safer.
“Compare it to climbing with or without oxygen,” concluded Furtenbach. “There will always be the idea of climbing by fair means, which basically means accepting a very high individual risk to die, harm your body, or damage the brain and other organs while climbing without oxygen. People opting for this style will do anything to make their climb riskier and more dangerous. The question is what for.”
