Henri B. Kagan of France and Kenso Soai of Japan have won the 2026 Nobel Prize in Chemistry for solving a century-old mystery about mirror-image molecules.

The Royal Swedish Academy of Sciences awarded the prize for the discovery of non-linear effects and autocatalysis in asymmetric organic synthesis. The announcement was made in Stockholm on October 7.

Many molecules come in left- and right-handed forms, like our hands. Living things use only one form, a puzzle called homochirality that chemists could not recreate in the lab.

Kagan showed in the 1980s how catalysts could tilt reactions toward one mirror form. Soai went further, designing a reaction in 2003 that produced only one form. The breakthrough helps drugmakers build safer medicines, since one mirror form may heal while the other harms.

The pair will share 12 million Swedish kronor, about $1.2 million. Soai said he was out shopping when the prize call came.