Human growth hormone (hGH) is necessary for:
- Growth when we are young
- Maintenance and repair and of our body after stresses such as exercise
- Combating the adverse effects of aging
You can increase hGH without a prescription. From this article The Exercise-Induced Growth Hormone Response in Athletes:
"Resistance training results in a significant exercise-induced growth hormone (EIGR) .…An exercise intensity above lactate threshold and for a minimum of 10 minutes appears to elicit the greatest stimulus to the secretion of hGH."