Reichstein is best known for his work with the hormones produced by the adrenal gland cortex. He established that these corticoids were steroids, and in 1936 was the first to isolate cortisone. Reichstein shared the 1950 Nobel Prize in physiology or medicine for his work with cortisone.

Reichstein was born in Wloclawek, Poland. His father was an engineer and the family lived in various European countries; they became Swiss citizens in 1914. Reichstein received his Ph.D. in 1922 from the Swiss Technical Institute (ETH), Zurich. In 1931 he became the assistant of Leopold Ruzicka (1887-1976), the Swiss biochemist who was an expert on ring structures and was working to synthesize sex hormones. Reichstein also synthesized corticoids from a derivative of bile acid so they could be used to treat Addison's disease, which results from the adrenal glands' failure to produce a normal amount of hormones. Reichstein determined the locations of the oxygen molecules that characterize the individual, but closely related corticoids, permitting their synthesis. He also conducted research on other steroids including those derived from plants.

Another of Reichstein's interests was the structure of vitamins. In 1933, he independently synthesized ascorbic acid (vitamin C ). In addition, he conducted research on pantothenic acid, one of the B vitamins.

Reichstein's many honors included honorary memberships in the U.S. National Academy of Sciences and the Royal Society (London). He also served as director of the Pharmaceutical Institute at the University of Basel. Reichstein retired in 1967 but he continued to conduct significant new research into his 90s. Reichstein died August 1, 1996.