Kagan and Soai win 2026 Nobel Prize in Chemistry for work on how one-handed molecules can emerge

The 2026 Nobel Prize in Chemistry has gone to Henri B. Kagan of Université Paris-Sud in France and Kenso Soai of the Tokyo University of Science in Japan. The Royal Swedish Academy of Sciences honoured them "for the discovery of non-linear effects and autocatalysis in asymmetric organic synthesis. The prize is about a puzzle in chemistry. Some molecules, such as amino acids, come in two versions that are mirror images of each other, like a left hand and a right hand. Living things use only one of the two versions.

Chemists call this one-handedness homochirality, from Greek words meaning "same" and "hand". Only one mirror version of each amino acid ends up in the proteins in your cells. The other is rarely found in nature.

For a long time, nobody could explain how this could start. When chemists ran reactions that can make both mirror images, they always got equal amounts of each in the test tube. Yet they wanted just one. In areas like medicines, only one mirror image usually has the effect they are looking for.

Henri Kagan took the first major step in 1986. He found a new way to steer chemical reactions, which let him make more of one mirror image than people had thought possible.

Kenso Soai went further. A key paper in 1995 described how he designed the first reaction with the potential to produce only one mirror image. In 2003 he got there. He presented a reaction in which only one of the two possible mirror images formed. According to the announcement, nobody except life itself had done this before.

"Henri Kagan and Kenso Soai have provided a solution to a chemical mystery that is over a century old: how homochirality can emerge spontaneously. The chemical reactions they have developed are spectacular," said Heiner Linke, chair of the Nobel Committee for Chemistry.

The Academy says their discoveries have been decisive for chemists who design reactions to make pharmaceuticals.