Who Discovered Insulin?

Insulin was discovered piece by piece, so its discovery cannot really be attributable to one person.  In 1869, Paul Langerhams, a German physician had written about the existence of clusters of tissues which existed in the pancreas.  These clusters were later found to release insulin into the surrounding blood capillaries.  These clusters were referred to as islets (actually the islets of Nagerhams, after the discoverer).  Attempts were then made to try and extract insulin through isolating it.  Insulin was the word derived from the latin meaning island, again referring to Langerhams find.
It was not until 1920 that Frederick Banting a Canadian surgeon began working at the University of Toronto with Charles Best, under the guidance of Professor John Macleod, with the specific aim of isolating insulin.  this was achieved around 1921 and by 1922 they had their own supply of insulin, which formed the first effective remedy for diabetes.

Banting, Macleod, Best and Collip, discovered Insulin was a treatment for Diabetes, in 1922.

Michael bliss