Krogh and his wife Marie brought insulin to Denmark shortly after its discovery in 1922 by Frederick Banting and Charles Best. Marie, a doctor who had patients with type 1 diabetes, was herself suffering from type 2 diabetes and was naturally very interested in the disease. Together with a doctor, Hagedorn, August and Marie Krogh founded Nordisk Insulinlaboratorium, where Krogh made decisive contributions to establishing a Danish production of insulin by ethanol extraction of the hormone from the pancreatic glands of pigs.