The scientist known for the discovery of insulin is Frederick Banting, along with his assistant Charles Best. In 1921, they successfully extracted insulin from the pancreas of dogs, demonstrating its potential to regulate blood sugar levels in patients with diabetes. This breakthrough revolutionized the treatment of diabetes, transforming it from a fatal disease to a manageable condition. Banting's work, which earned him the Nobel Prize in Physiology or Medicine in 1923, has had a lasting impact on medical science and the lives of millions affected by the disease.