
Originally Posted by
Sgt. Hartman
Actually, taking any significant amounts of GH regularly will shut natural production down. GH serum levels and IGF-1 levels both regulate natural GH release and since GH levels will be elevated for roughly 12 hrs and IGF-1 for around 20 hrs after pinning your natural pulse will be suppressed. I have a bunch of studies on it if anybody wants to see them.
But I've never heard of natural GH being permanently suppressed after discontinuing rHGH. The pituitary is much more resilient than the HPTA and typically picks back up right where it left off.