Loretan was the third person to climb all 14 eight-thousanders (second without oxygen), a feat he accomplished at the age of 36. He made his first expedition to the Andes in 1980 and began climbing the eight-thousanders in 1982 with an ascent of Nanga Parbat. Thirteen years later, in 1995, he climbed the last of them, Kangchenjunga. In 1986, together with Jean Troillet, Loretan made a revolutionary ascent of Mount Everest in only 40 hours, climbing by night and without the use of supplementary oxygen.