This whole thread looks confusing, probably especially to any newbies.
Here's the way I understand it:
Body makes a certain amount of GH, testosterone, and insulin. We know that, right?
We all know that taking larger amounts of testosterone than what occurs in the body causes a greater increase in muscle size in training adults. Testosterone's job in essentially simple terms, is "build more muscle" for our purposes here.
GH when taken in larger amounts causes a shift from storing fat and burning glycogen to burning fat and preserving lean muscle. Also causes growth of nearly every tissue. Established, right?
Insulin's job is to regulate blood sugar. It draws nutrients into the cells and typically will store any extra as fat. Anyone who has taken insulin knows that if they take a lot and don't compensate with an intake of carbs, their blood sugar drops. Again, established, correct?
So to grow like the pros do, you must combine these three things with enough training and fuel. Having supraphysiological levels of all three components then act as so in response to heavy training and food: Huge amounts of testosterone/gear tell the muscles to grow, GH tells the body to preserve the muscle and burn fat and tells the tissues to grow, insulin causes the muscle cells to take in more of the fuel you give them--but because GH is telling the body to burn fat and not store it, the insulin won't generally make you fat (all else being equal). Again we're only talking simplistically here. There are obviously many other factors that are involved, and everyone responds differently, but for the basics to really truly grow as the pros do, this is what you would need.
Pros understandably take large amount of each of these components (regardless of whether this is healthy or not). Most pros typically won't tell you what they take or their dosages. The closest we get is when one spills something like Seth Feroce saying he took in the neighborhood of 20 iu of GH at one point. Look at the size of these pros. Muscles huge like a cartoon on most of them. You cannot achieve this without large amounts of all three components, genetics aside. Of course hyper responders who are genetically gifted grow so much better than the average person and not get sick on the huge amounts they use.
Refer back to BigA's thread:
https://www.professionalmuscle.com/forums/professional-muscle-forum/53353-so-sick-heres-truth.html