Henri Kagan and Kenso Soai win 2026 Nobel Prize in Chemistry

French chemist Henri B. Kagan and Japanese chemist Kenso Soai have won the 2026 Nobel Prize in Chemistry for discoveries involving non-linear effects and autocatalysis in asymmetric organic synthesis, the Royal Swedish Academy of Sciences announced Wednesday.

Their work addressed a longstanding question about chirality, or why molecules can occur in two forms that are mirror images of each other but cannot be superimposed. Living organisms generally use only one of these forms in key molecules such as amino acids, a property known as homochirality. Producing only the desired form is also important in pharmaceutical development because mirrored versions of a molecule can have different effects.

Kagan made a key advance in 1986 by showing that a small excess of one mirror-image catalyst could generate a much larger excess of the corresponding product. Soai subsequently developed an autocatalytic process in which the reaction product drives production of more molecules with the same handedness. The Nobel committee said his work culminated in a 2003 demonstration of a reaction that produced only one of the two possible mirror images.

“Henri Kagan and Kenso Soai have provided a solution to a chemical mystery that is over a century old,” Nobel Committee for Chemistry chair Heiner Linke said.

Kagan is affiliated with Université Paris-Sud in France, while Soai is affiliated with Tokyo University of Science. They will share the award of 12 million Swedish kronor and are due to receive their medals in Stockholm on Dec. 10.