My first 5 days of HGH use was on the yellow top somatropin from China. I barely felt anything, maybe a slight pump throughout the day, but nothing much. My next 5 days was on Somatropin by Genotropin (brand name), and WOW! My body temperature went way up, to where my AC was at 71 degrees fahrenheit, and my fans were on full blast, and I still couldn't get cool enough. My energy levels were up, and I was moving through sets in my workout faster than I ever have. I felt I had a near full bicep pump after 1 set of pull downs. To those of you who say you don't notice anything on HGH until a couple of months, well...you've never had Genotropin. According to my father, this is the best HGH money can buy. I know I can't name prices, but I'll just say that it costs 5x more AT WHOLESALE PRICE than the chinese HGH off the street. Has anyone else ever used/heard of this stuff?