GH is released in the body in "pulsatile intervals" the biggest which occurs during initiation of slow wave sleep like somewhere an hour after you go to sleep. Around 2/3rds or so is released while you sleep with lesser amounts during the day obviously.
Chronic training has shown to depress GH levels (as with all other hormone levels except like cortisol and such -- hence a somewhat overreach/overtraining effect), but in general a training effect will increase GH release overall.
I think there's something which ties in GH release to increases in body temperature but I'm a bit fuzzy on the details now. Hence why higher intensity training may release more GH than lower intensity exercise such as cardio and whatnot.
Decreases in overall GH production and increases in cortisol production happen during normal senecesnce (e.g. the aging process) during sleep.
Regardless, since GH is a polypeptide I suppose it's a bit safer than the steroid hormones in regards to side effects and ability to screw up your body. Generally, fat soluble substances tend to exert larger effects on the body, but they tend to have bigger side effects if things get out of whack (see fat soluble vs. non fat soluble vitamins).
If you were going to dope performance, healing, or anti-aging or whatever I'd go with this over any type of cholesterol derived steroids.
Although vitamin D has shown so good effects in increasing muscle mass and strength as it's a seco-steroid (since it's produced from cholesterol) so that's another route you can take especially if you're deficient.
Not that I would recommend doping in any way or form.....
Dialing in training, sleep, nutrition, stress should tend to give better results anyway (unless you're already dialed in).
Last edited by Steven Low; 05-18-2011 at 11:28 AM.