John Macleod was a Scottish physiologist and Nobel Prize winner, best known for his discovery of insulin. Born on September 6, 1876, in Cluny, Scotland, he studied at the University of Edinburgh and later worked at the University of Toronto. His research significantly advanced the understanding of diabetes and its treatment. In 1923, Macleod shared the Nobel Prize in Physiology or Medicine with Frederick Banting for their work on insulin. This breakthrough transformed diabetes management, allowing patients to control their blood sugar levels effectively. Macleod's contributions to medical science have had a lasting impact on the treatment of diabetes.