Bro, you asked this question exactly 1 week ago here! And I remember very specifically Bigz one of our admins here said he likes to use IGF 1 lr3 due to it being more immediate. and some others chimed in as well with their answers.
So why are you asking this again, and where are you reading if your coming away with Most people Use Human Growth Hormone HGH to bulk? Thats not my take on it!
HGH like anything else, can be used in a bulk or cutting cycle, and HGH is usually run with Insulin, preferably the faster acting insulins like a Humalog , though most people use Humalin R due to it being more readily available without a prescription, and of course cytomel t3 and / or t4 is used alongside your HGH and Slin!
It however is my experience that IGF 1 lr3 is a much better choice over HGH, making HGH in my humble opinion nearly obsolete for most people! Although hgh does have some other benefits due to it converting to many other growth factors, but for the money and for the purposes of building muscle, and losing fat, IGF 1 lr3 is the way to go