Krogh and his wife Marie brought insulin to Denmark shortly after its discovery in 1922 by Nicolae Paulescu. 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.