Henri B. Kagan and Kenso Soai won the 2026 Nobel Prize in Chemistry on October 7 for showing how chemical reactions can produce one preferred mirror-image form of a molecule, helping explain the “handedness” of life and improving the design of medicines.
The Royal Swedish Academy of Sciences honored the scientists for discovering nonlinear effects and autocatalysis in asymmetric organic synthesis. Many molecules exist in two forms that resemble left and right hands, but living organisms overwhelmingly use only one version of certain compounds, including amino acids in proteins. This preference, known as homochirality, has puzzled chemists for more than a century.
Kagan made an important advance in 1986 by demonstrating that chemical reactions could amplify a small imbalance between the two molecular forms. Soai later developed a reaction with the potential to become entirely one-sided and, in 2003, produced only one mirror-image form from a non-chiral starting mixture. Their work gave chemists a clearer explanation of how molecular asymmetry can emerge and provided practical tools for controlling it.
The findings are especially important in pharmaceutical chemistry, where two mirror-image versions of a drug can interact differently with the body.