The purpose of insulin in bodybuilding is to keep blood sugar in the correct range
This only happens if you're taking a large amount of HGH. Taking more insulin to gain more weight will only cause insulin resistance and stops working after a few weeks
Secondly, no-one uses IGF-1. To my knowledge there is only one person in the world supplying IGF-1 to athletes and it's this French guy called "Mr Increlex"
Lastly, I have had the opportunity to speak with many high level strength athletes. This includes Stan Efferding, Andrey Malanichev, Eric Lilliebridge, Brandon Lilly and many more, too many to list. No-one uses HGH in powerlifting. Literally no-one. The muscle you gain from HGH is not like the muscle you gain from Androgens as far as strength goes. Most top level strength athletes simply take as much testosterone as they can deal with, which normally sits around 1-5 grams weekly