I just got some of the Norditropin Flex pro 15 mg/1.5 mL prefilled pens in. This will be my first time taking anything. I would like to know if anyone has taken this, the results, and how many iu's I should take a day? I am wanting to gain muscle mass. Is it best to pen in the stomach area or where? I do not want to take test or anything with it because I want to keep my gains as much as possible and I have researched that HGH you could keep most of your gain. I also am scared of gyno and other side effects of the other cycles. Any advice and tips would be much appreciated, and anything you think that would be helpful when taking this please feel free to fill me in on the info you have learned about this.