Can anyone tell me what to think about my IGF-1 test results?

I'm almost 50 and my initial test was 168 ng/ml. I started taking about 3 iu of HGH daily and had another blood test done 3 days later. It reported that my IGF-1 was 191 ng/ml. I had anticipated an increase much larger that that ?!? (from 168 to 191)

Should I find a different source for my HGH or take another test? Something is not right and I could use some good advise. I figure that I should be up around 400 - 500 ng/ml IGF-1. I took the tests to make sure I'm not being taken with fake HGH. I've been taking 1.5 iu twice daily and do think that my joints feel stronger. I think I am seeing some improvement already but am not sure what to do to protect myself.

I really hate to give a doctor $1000+ every month, when there are better more efficient ways to get what I need.

Thanks for looking at this and for this great forum !!!