Glutamate is an amino acid with very different functions: in the pancreas, it modulates the activity of the pancreatic ß--cells responsible for insulin production, whereas in the brain it is the main excitatory neurotransmitter. In recent years, it has been suspected to play an additional role in the functioning of the brain. By discovering how the brain uses glutamate to produce energy, researchers confirm this hypothesis and highlight unexpected links with the rest of the body.