Normally your pancreas produces all the insulin your body needs. When you have type 1 diabetes, however, your pancreas does not produce any insulin. You must get insulin from an outside source.
When you have type 2 diabetes, your body doesn't produce enough insulin, and your body can't use it well. You may need to supplement your body with insulin from another source. The insulin that you take is made in a laboratory so that it is identical to human insulin.