Kagan and Soai Win Nobel Prize in Chemistry for Molecule Discovery
Henri Kagan and Kenso Soai have been awarded the 2026 Nobel Prize in Chemistry for developing methods to produce single mirror-image forms of molecules, work critical to safe drug development.
Newsnibs Staff
- 2026-10-10
- Updated 3:22 PM UTC
(Stockholm, Sweden)
Henri Kagan and Kenso Soai have won the 2026 Nobel Prize in Chemistry for developing methods to produce a single mirror-image form of a molecule rather than a mixture of both. The prize, announced Wednesday, carries 12 million Swedish crowns, about $1.2 million, to be split between the two laureates.
Kagan, 95, is affiliated with the Université Paris-Sud in Orsay, France. Soai, 76, is affiliated with the Tokyo University of Science in Japan. Kagan is the third-oldest person ever awarded a Nobel Prize.
Many molecules exist in two mirror-image versions, as recognized since French chemist Louis Pasteur's 19th-century work on tartaric acid. The two forms of a given molecule can behave very differently: one version of carvone smells like mint, the other like caraway. Living organisms use only one mirror-image version of certain molecules, a phenomenon called homochirality.
The distinction matters most in medicine. Peter Somfai of the Nobel Committee for Chemistry said "the left-handed version of the drug can have one effect, and the right-handed version can have another effect." The thalidomide scandal of the early 1960s, in which the wrong mirror-image form of a drug caused birth defects, is the case most often cited to illustrate the danger of getting this wrong.
Kagan's work in the 1980s first showed that chemical reactions could be designed to favor one mirror-image form over the other. Soai later developed what is known as the Soai reaction, described as the first efficient reaction to produce only one mirror-image form of a molecule. Rigoberto Hernandez, president of the American Chemical Society, said "the medicines we have today would not be possible without this chemistry."
Soai was grocery shopping when he learned he had won. "This is the most exciting day in my life, I am very glad to share this prize with Professor Henri Kagan," he said. Japanese Prime Minister Sanae Takaichi told him, "As a Japanese, I'm very proud of you." French President Emmanuel Macron called the award "an immense source of pride for the country" and "a recognition suited to a lifetime of research." Kagan could not be reached for comment; his daughter, Veronique Le Deunff, said she was "very happy" and that her father's research had "opened up new avenues for research."
Kagan and Soai will receive their medals from Sweden's King Carl XVI Gustaf at a ceremony in Stockholm on December 10.
Photo by Terry Vlisidis on Unsplash
