The Science Behind the 2026 Nobel Prize in Chemistry

The 2026 Nobel Prize in Chemistry has been awarded to French chemist Henri B. Kagan and Japanese chemist Kenso Soai, for their research into mirror-image molecules. Their discoveries have helped scientists understand how chemical reactions can favour one form of a molecule over another, with relevance to pharmaceutical research and our understanding of the origins of life.  

The Royal Swedish Academy of Sciences recognised the pair for their work on non-linear effects and autocatalysis in asymmetric organic synthesis. At the heart of their research is a simple question: how can chemists encourage a reaction to produce one version of a molecule rather than its mirror image? 

Some molecules exist in two forms that are mirror images of each other. These forms are known as enantiomers. Although they contain the same atoms, their different arrangements can affect how they interact with other molecules, including those on living organisms. As a result, one form of a molecule may be beneficial while the other may be ineffective or even harmful.  

This is especially important in medicine. Controlling which molecular form is produced can be essential to developing and manufacturing pharmaceuticals, where producing the correct version of a molecule can determine whether a drug works as intended.  

Kagan’s breakthrough came in 1986, when he demonstrated that a small imbalance between the mirror-image forms of a catalyst could lead to a much larger imbalance in the products of a chemical reaction. This is known as a non-linear effect, where a small initial preference for one form can have a disproportionately large influence on the final result. 

Building on this work, Soai investigated autocatalysis, a process in which a reaction product helps catalyse its own formation. In 1995, he published research describing a reaction that could amplify a small preference for one mirror-image form, and by 2003, he had demonstrated a reaction that produced only one of the two possible forms. This achievement provided a potential explanation for homochirality, the phenomenon whereby life on Earth uses molecules of one particular handedness.  

Together, their discoveries helped explain how one molecular form can come to dominate over its mirror image, shedding light on homochirality – the preference for particular molecular forms in living organisms. Scientists have been trying to understand how this preference arose for over a century.  

Commenting on the award, Heiner Linke, Chair of the Nobel Committee for Chemistry, said the discoveries offered a solution to a scientific mystery that has puzzled researchers for more than a century, describing the reactions developed by Kagan and Soai as “spectacular”. 

Their research has helped chemists gain greater control over the production of different molecular forms, an important consideration in pharmaceutical manufacturing, where the structure of a molecule can affect how a medicine works.   

The pair will share the 12 million SEK prize fund, with each receiving a gold medal and diploma. In short, their work helps explain why life favours particular molecular forms. Beyond that, it explains how life also continues to shape the way modern chemists design and produce molecules for use in medicine and industry.  

Words by Olivia Medlicott