Our glycaemic balance is based on the ability of the pancreatic beta cells to detect glucose and secrete insulin to maintain our blood sugar levels. If these cells malfunction, the balance is broken, and diabetes develops. Until now, the scientific community agreed that beta cells needed the other hormone-producing cells of the pancreas to function properly. A team has now demonstrated the opposite: in adult mice whose pancreas contains only beta cells, glycaemia regulation and insulin sensitivity are even better than in standard animals.