Some molecules, such as amino acids, exist as two variants that are each other’s mirror image. However, living organisms only contain one of these mirror images. How chemical asymmetry such as this could have emerged was long a mystery to chemists. Henri B. Kagan and Kenso Soai are awarded the Nobel Prize in Chemistry 2026 for discovering a solution to this puzzle.
Life’s chemistry is what chemists call homochiral, after the Greek words for “same” and “hand”. Like hands, all amino acids exist as two mirrored variants, but only one of them is found in the proteins in your cells. The other is rarely found in nature.
For a long time, chemists wondered how homochirality can emerge. When they began to experiment with chemical reactions that can form two mirrored molecules, they always obtained equal proportions of both in their test tubes. However, chemists strived to produce only one of these mirror images, because in the development of molecules that will interact with living beings – such as in pharmaceuticals – only one mirror image will have the desired effect.
The Nobel Prize in Chemistry 2026 recognises discoveries that have enabled chemists to drive chemical reactions that lead to homochirality.
“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,” says Heiner Linke, chair of the Nobel Committee for Chemistry.
Henri Kagan took the first decisive step in 1986, when he discovered a new way of manipulating chemical reactions. This allowed him to create a greater excess of one of the mirror images than had previously been thought possible.
Kenso Soai took the next step. In 1995, a key publication describes how he designed the first ever chemical reaction that had the potential to be homochiral. In 2003, he finally succeeded. He presented a reaction in which only one of the two possible mirror images was formed. Other than life itself, no one had previously achieved this feat.
Thanks to Henri Kagan and Kenso Soai, we now know how homochirality can emerge. Their discoveries have been decisive for chemists who design reactions for the manufacture of pharmaceuticals.
Illustrations
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Read more about this year’s prize
Popular science background: They solved chemistry’s asymmetric mystery (pdf) Scientific background to the Nobel Prize in Chemistry 2026 (pdf)
Henri B. Kagan, born 1930 in Boulogne-Billancourt, France. PhD 1960 from Collège de France, France. Professor Emeritus at the then Université Paris-Sud, France.
Kenso Soai, born 1950 in Hiroshima, Japan. PhD 1979 from University of Tokyo, Japan. Professor Emeritus at Tokyo University of Science, Japan.
Prize amount: 12 million Swedish kronor to be shared equally between the laureatesFurther information: www.kva.se and www.nobelprize.orgPress contact: Eva Nevelius, Press Secretary, +46 70 878 67 63, [email protected]Expert: Peter Somfai, +46 70 693 63 77, [email protected], member of the Nobel Committee for Chemistry
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