Henri Kagan and Kenso Soai have been awarded the 2026 Nobel Prize in Chemistry for resolving a long-standing scientific puzzle involving asymmetric “mirror image” molecules, a breakthrough with significant implications for the pharmaceutical industry. The announcement was made on Wednesday by the Nobel committee.
Soai, aged 76, hails from Japan, while Kagan, 95, is French. Their research builds upon foundational work by 19th-century French chemist Louis Pasteur. Speaking by phone during the Nobel Prize press conference, Soai described the day as “the most exciting in my life” and expressed his happiness in sharing the prize with Kagan. At the time of the announcement, Soai was out shopping. The committee was still attempting to reach Kagan to inform him of the honor.
The Chemistry Nobel, traditionally the third prize announced during Nobel week, followed the awards for medicine and physics revealed earlier in the week.
Many biologically essential molecules exist in two forms that are mirror images of each other, comparable to left and right hands. However, living organisms almost exclusively utilize one form, a phenomenon known as “homochirality,” derived from the Greek word for hand. This has been a perplexing issue for chemists for over a century.
This year’s prize recognizes discoveries demonstrating how chemical reactions can be directed to favor one molecular mirror image over the other. Such control is vital for chemists designing processes to manufacture pharmaceuticals. Peter Somfai, a member of the Nobel Committee for Chemistry, explained that the left- and right-handed versions of a drug can produce different effects, necessitating methods to selectively produce the desired form. The laureates’ findings have provided powerful tools to achieve this selectivity.
Their work traces back to Louis Pasteur, who first identified molecular chirality while studying tartaric acid, a compound important in winemaking. Pasteur observed that bacteria only ferment one form of tartaric acid naturally found in grapes, while the other form does not undergo fermentation. This discovery established that substances could exist in two forms with distinct properties, sometimes with serious health implications.
Kagan and Soai advanced this understanding by developing asymmetric reactions that generate an excess of one molecular form. Their research has practical importance, highlighted by the thalidomide tragedy in the early 1960s, when thousands of children were born with birth defects caused by one mirror image of the drug thalidomide, while the other form was safe.
The Nobel Prizes were established by the will of Swedish inventor Alfred Nobel and have been awarded since 1901, with interruptions mainly due to world wars. Nobel, a chemist by training, accumulated wealth from inventions related to warfare, including dynamite. The economics prize was added later and is funded by the Swedish central bank.
While sometimes overshadowed by laureates in physics, literature, and peace, the chemistry prize has recognized many groundbreaking discoveries, such as nuclear fission and genetic sequencing techniques. Last year’s chemistry award honored Susumu Kitagawa, Richard Robson, and Omar Yaghi for developing metal–organic frameworks, which address challenges like climate change and water scarcity.
The 2026 laureates will receive their medals from Sweden’s King Carl XVI Gustaf at a ceremony in Stockholm on December 10, the anniversary of Alfred Nobel’s death. The event will be followed by a formal banquet at Stockholm City Hall. They will share a prize sum of 12 million Swedish crowns (approximately $1.2 million) and join the ranks of the world’s most prestigious science award winners. The Nobel Peace Prize, the only one awarded outside Sweden, is presented separately in Oslo.
Leave an opinion