First off, I am not arguing against the practise as there seems to be overwhelming anecdotal evidence in favour of it, nor am I trying to find a cheap alternative as I am personally 4 months into a 8 month+ jin run, I am just trying to understand why it is necessary.
The most often quoted reason seems to be that ones IGF levels are raised over time, this is the part that I don't fully understand as I was under the impression that GH and the resultant IGF is in and out of the body in a matter of hours - so how does it "build up" over the weeks & months?