(+/-)- Adomeglivant, also known as LY2409021, is a potent and selective glucagon receptor antagonist. LY2409021 lowers blood glucose in healthy people and in those with type 2 diabetes. Blockade of glucagon signalling in patients with type 2 diabetes is well tolerated and results in substantial reduction of fasting and postprandial glucose with minimal hypoglycaemia, but with reversible increases in aminotransferases. Inhibition of glucagon signalling by LY2409021 is a promising potential treatment for patients with type 2 diabetes and should be evaluated in longer clinical trials to better evaluate benefits and risks.