Natural shutdown will happen with age regardless of use.
Cadaver studies have shown that elderly men (sorry, I can't remember the exact age) have an abundance of hGH in their pituitary gland. The naturally occurring age-related decline in circulating GH levels is due not to a hormone manufacturing problem, but a releasing one.
first statement: one dimensional view (missing the big picture)
second: state source
at the moment, there is too little known about these ghrh secretagogues and it's positives/negatives
right now, all you have are so-called "fountain of youth" formulas that address the superficial well-being factors but worsen the internals
there is not yet a way to maintain/repair internal cellular regeneration
telomere-related or micro-bacterial studies/advances are two of the main leads but probably it's not for this time yet
to summarise: in a subject that wishes to promote his daily T-levels for a prolonged period of time (upper or slightly above physiologic range), there is a big difference in whether he would use pregnyl injections or test replacement. If you can understand the difference and it's implications, there you go
