On 7 October 2026, the Royal Swedish Academy of Sciences announced the laureates of the Nobel Prize in Chemistry. The award went to the French scientist Henri B. Kagan and the Japanese researcher Kenso Soai.
The prize was awarded "for the discovery of nonlinear effects and autocatalysis in asymmetric organic synthesis." Their work explained how homochirality — a preference for one of the two mirror forms of molecules — can arise spontaneously in chemical reactions.
Many molecules, including amino acids, exist in two variants that are mirror reflections of each other. Living organisms use only one of these forms. How such selectivity arose remained a mystery for more than a century.
Kagan, professor emeritus at the University of Paris-South, showed back in the 1980s how catalysts could be used to obtain a substantial excess of one mirror form. His discoveries proved revolutionary for the pharmaceutical industry.
Soai, professor emeritus at the Tokyo University of Science, developed these ideas further. In 2003, he created a reaction in which only one chiral form is formed from achiral starting materials — the first time under laboratory conditions.
"Henri Kagan and Kenso Soai offered a solution to a century-old chemical mystery: how homochirality can arise spontaneously. The reactions they developed are impressive," noted Heiner Linke, chairman of the Nobel Committee for Chemistry.
The laureates' work has direct significance for drug production: one mirror form of a drug may be effective, while the other may cause side effects. Chemists can now deliberately obtain the desired variant.
Soai, who learned of the award while out shopping, said by phone at a press conference: "This is the most exciting day of my life. I am very glad to share the prize with Professor Henri Kagan."
The prize of 12 million Swedish kronor will be divided equally between the laureates. But how nature, billions of years ago, made its choice in favor of one mirror form — that question still intrigues scientists.
