Like "Here's a MedicineNet article which tells about "insulin sources". It is the result of a google search on that term: http://www.medterms.com/script/main/art.asp?articlekey=3989 There are 3 main sources pork insulin, beef insulin and recombinant human insulin Part of the article says: "Insulin was the first hormone to be synthesized completely in the laboratory, a feat accomplished in 1966 by the American worker Michael Katsoyannis and scientists in China. The first recombinant human insulin was approved by the FDA in 1982." and No Krystal it's not a wierd question. I thought I knew, but it caused me to research it, and I now know more than I did before because of your question. Thank you!"