Henri Kagan, 95, of France and Kenso Soai, 76, of Japan won the 2026 Nobel Prize in Chemistry on October 7, according to reports, for their work on chirality — the “mirror image” problem in molecules — and how chemical reactions can be driven to favour a single mirror-image version of a molecule.
Many molecules exist in two forms that are mirror images of each other, like left and right hands: identical in composition, but not superimposable. The puzzle at the heart of the laureates’ work is how to make a reaction produce predominantly one of those two versions rather than an equal mixture of both. Solving that problem matters enormously in practice, because the two mirror forms of a molecule can behave very differently inside the human body — a fact of central importance to pharmaceutical manufacturing, where the wrong mirror version of a drug compound can be ineffective or worse.
Living organisms themselves almost exclusively use one version, a property known as homochirality, and why life settled so decisively on a single handedness has remained one of science’s enduring questions. The puzzle stretches back to Louis Pasteur, whose early work on molecular asymmetry in the nineteenth century first revealed that mirror-image forms of molecules behave differently. Kagan and Soai’s contributions helped turn that curiosity into practical chemistry, giving researchers ways to steer reactions toward a chosen mirror-image product.
According to reports, the prize recognises the two chemists for solving aspects of this mirror-image problem, work described as hugely important for pharmaceutical manufacturing. Modern drug production routinely depends on obtaining single-handed molecules in pure form, and the methods and insights associated with the laureates’ research underpin parts of how industry approaches that challenge.
The award, announced on October 7, also stands out for the ages of its recipients: Kagan is 95 and Soai is 76, and their recognised work speaks to research programmes pursued over long careers in France and Japan respectively. According to reports, the Nobel Prize in Chemistry for 2026 went jointly to the two for their advances on chirality.
Beyond the laboratory, the recognition draws attention to a question that is at once practical and profound — why nature builds with one hand rather than the other — and to the chemists who found ways to make human-made reactions do the same. For the pharmaceutical industry, where mirror-image purity can decide whether a medicine works as intended, the work honoured this week in Stockholm remains part of the foundation of modern drug making.