Insulin is a natural hormone that is secreted from the pancreas in response to high sugar levels. Its main use is to regular sugar levels in the body. The use of insulin in body building is a controversial subject as using it is constituted as steroid use and it is used to enhance a body building workout.
When blood sugar levels are high, insulin works to increase the storage of glucose which provides energy to the body. The benefit of insulin use in body building is to provide more energy which allows for longer and more intense workouts. While insulin does make for a conducive anabolic environment in the body, it can truly do more harm than good.
Diabetics are not able to produce their own insulin which is why they must either take synthetic insulin or control their insulin production through diet. If you are not a diabetic, taking insulin when you don’t need it will cause your pancreas to stop producing it naturally. What is the end result of that? You will essentially become a diabetic.