in all honesty i think its a couple of major factors
first - nearly 20 years of fairly heavy usage, pretty much non-stop
second - an assload of GH, again for many years, at times up to 20ius per day
now, obviously i don’t recomend such things but luckily for me, having worked for a few years now with a functional medicine specialist and having tested damn near every thing that can be tested on a human being…i have no real health issues at all, i easily maintain 260lbs or so on just 100-200mg of test per week by prescription. occasionally i have been known to throw in a short burst of somthing like test prop / masteron for about 4 weeks out of every 12 but thats prety much it. not even 10% of what i use to take constantly. I guess you would call it overkill theory…do it long enough and things just change.
If you have specific questions i would prefer they be taken off board because people get the wrong idea and next thing you know someone wants to argue. you know BBB obviously…he has my email