Stockholm — Kagan and Soai Win 2026 Nobel Chemistry Prize

The Royal Swedish Academy of Sciences awarded the 2026 Nobel Prize in Chemistry to Henri Kagan and Kensō Soai for designing reactions that produce only one of the two mirror-image forms of a molecule, according to the Nobel Committee for Chemistry, cited by WIRED.

What did Kagan and Soai actually discover?

Many molecules are chiral, meaning they exist as two mirror-image forms — called enantiomers — that share physical properties but can behave differently inside the body, the Nobel Committee said, per WIRED. Living organisms overwhelmingly contain just one of the two forms, a phenomenon called homochirality. Kagan and Soai each built chemical reactions that force a synthesis toward one enantiomer instead of the usual 50-50 mix, giving chemists a controllable tool rather than a matter of chance.

Why does the mirror-image problem matter for medicine?

In drugs built from chiral building blocks such as amino acids or sugar molecules, one enantiomer can deliver the intended therapeutic effect while its mirror twin causes unwanted or harmful side effects, the Nobel Committee said. Nobel Committee for Chemistry chairman Heiner Linke used a locksmith's analogy to explain the stakes, according to WIRED:

"Only one of them fits the lock — and the lock can be damaged if your customers try to unlock it with the other key."

Why has chemical asymmetry puzzled scientists since Pasteur?

The mystery dates to Louis Pasteur, who found that two enantiomers of the same compound reacted very differently when exposed to bacteria, WIRED reported. Early 20th-century attempts to reproduce nature's selectivity in the lab mostly failed, yielding roughly equal amounts of both mirror forms instead of the lopsided ratios seen in living cells.

What dates mark the path to this year's prize?

• 1953: Theoretical physicist Charles Frank proposed a mathematical model laying out three conditions needed to reproduce homochirality, including a self-reinforcing "autocatalysis" loop, per WIRED.
• Early 1980s: Henri Kagan began the line of research that built on Frank's framework, according to WIRED.
• 2026: The Royal Swedish Academy of Sciences named Kagan and Soai as this year's Chemistry laureates, WIRED reported.

What did earlier chemists get only partly right?

German chemist Willy Marckwald, working at the start of the last century, designed an asymmetric reaction using a chiral catalyst — a substance that speeds a reaction without being consumed — that nudged production toward one enantiomer, WIRED reported. The shift in ratio, however, was small. Frank's 1953 model later supplied the theoretical conditions, including autocatalysis, that explained why a tiny initial imbalance could snowball until one mirror form dominated a reaction, setting the stage for the laureates' later work, according to WIRED.

For the full account of the laureates' methods and the committee's reasoning, see WIRED's report.