In 1933, working in Zürich, Switzerland, Reichstein succeeded, independently of Sir Norman Haworth and his collaborators in the United Kingdom, in synthesizing vitamin C (ascorbic acid) in what is now called the Reichstein process.
Together with Edward Calvin Kendall and Philip Showalter Hench, he was awarded the Nobel Prize in Physiology or Medicine in 1950 for their work on hormones of the adrenal cortex which culminated in the isolation of cortisone.
He died in Basel, Switzerland. The principal industrial process for the artificial synthesis of Vitamin C still bears his name. Reichstein was the longest-lived Nobel laureate at the time of his death, but was surpassed in 2008 by Rita Levi-Montalcini.