Climbing Mount Everest typically takes weeks, with most of that time spent at the foot of the mountain adjusting to the thin air. But four British men last week shrank that timeline dramatically, traveling from London to the summit and back in less than a week, according to the organizer of their expedition.

They skipped the adjustment period, in part, by inhaling a secret weapon: xenon gas.

Their feat has roiled the world of mountaineering and prompted an investigation by the Nepalese government, as use of the gas is fiercely debated. Some research has shown that xenon can quickly acclimatize people to high altitudes, even as some experts say the benefits, if any, are negligible and the side effects of its use remain unclear.

Organizers said the gas was key to the speed of the climb, but their approach has prompted a broader debate that strikes at the core of mountaineering: Should scaling Mount Everest, one of sporting’s greatest accomplishments, be made easier — available to more people during a quick vacation — with the help of a performance enhancer?

“It is a provocation, especially for traditional mountaineers, who feel bad about this idea that you can climb Everest in less than a week,” Lukas Furtenbach, who organized the exhibition, said in a phone interview from the base of the mountain. “This showed that it can work.”

Mr. Furtenbach said that beginning in 2026 he planned to offer two-week round-trip excursions to Mount Everest using xenon gas, cutting the typical time needed to scale the mountain by several weeks.

“This can be the future of commercially guided mountaineering on Mount Everest,” he said.

With Xenon, ‘you feel better.’

For those who live at lower elevations and have traveled to the mountains, the discomfort of altitude sickness is all too clear. Symptoms include nausea, headaches and disrupted sleep, and in some cases it can lead to brain swelling, or even death.