The final push for the summit was dramatic: Buhl continued alone for the final , after his companions had turned back. Under the influence of the drug pervitin (based on the stimulant methamphetamine used by soldiers during World War II), padutin, and tea from coca leaves, he reached the summit dangerously late, at 7:00 p.m., the climbing harder and more time-consuming than he had anticipated. His descent was slowed when he lost a crampon. Caught by darkness, he was forced to bivouac standing upright on a narrow ledge, holding a small handhold with one hand. Exhausted, he dozed occasionally, but managed to maintain his balance. He was also very fortunate to have a calm night, so he was not subjected to wind chill. He finally reached his high camp at 7:00 p.m. the next day, 40 hours after setting out. The ascent was made without oxygen, and Buhl is the only man to have made the first ascent of an peak alone.