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.
Under sitt arbete i Zürich 1933, lyckades han, oberoende av Sir Norman Haworth och dennes medarbetare i Storbritannien, syntetisera vitamin C (askorbinsyra) i vad som nu kallas Reichstein-processen.