Allegedly....
If you're looking to get really huge either as a bodybuilder or not, then actually you need Growth, Test, and slin. The only reason HGH works like it does is when there is also a huge growth stimulus and calorie surplus. You can only get that if you use slin with it. Use say, 800mg test, 40 iu/day HGH, and as much slin as you can tolerate (you'll have to find out by incrementing slowly), eating as much as you can to be in a calorie surplus plus deal with the slin (won't go into the macros here), and you'd pack on some serious size. The drawbacks of course are the cost and the length of time you have to run HGH, usually for a good 8 months to a full year, and you HAVE to watch what you do with the slin, for obvious reasons. This is simplified of course for someone who may not want to compete.

Allegedly....