That stuff is all a scam, and just a bunch of garbage. It's mostly just arginine (a basic non-essential) amino acid. Actual HGH is like a supercharger on a car, and any "human growth complex" you can get at Vitamin World is like a K&N sticker that douchebags put on their windows.
Any supplement site and most stores will have some type of prohormone though, and those are just shitty steroids in a different package. People would really be better off using actual gear if that is what they choose to do, but the prohormones are legal so they get a lot of use. Every year or so a bunch of them get scheduled, and then new stuff comes out.