There's good evidence that a protein drink (carbs + protein) after workouts is beneficial to cyclists.

As far as diet vs. supplements...

I wish that either 1) I could get all this nutrition from my food at effective concentrations, or 2) I just didn't find improvements with supplements. Unfortunately, these aren't true for me. I don't take anything but Emergen-C now but that hasn't always been the case.

One more note...

You mentioned HGh. Human Growth Hormone is very different than the other substances you mentioned. It's very expensive, and should be intravenously injected for full effect. The results are dramatic. As with many hormones or "prohormones", there risks involved with its use. I'd read up extensively before giving any particular product in this category a whirl. There's a lot of dishonest marketing, mislabeling and inaccurate measurements of product weights in this space along with a radical disregard for consumer safety.