A study led by the University of Bonn has identified a molecule – the purine inosine – that boosts fat burning in brown adipocytes. The mechanism was discovered in mice, but probably exists in humans as well: If a transporter for inosine is less active, the mice remain significantly leaner despite a high-fat diet. The study, which also involved researchers from the University of Leipzig and the University Medical Center Hamburg-Eppendorf, has now been published in the journal Nature.