My theory is that HGH is man’s hormone of survival. The survival of the fittest in primitive humans was real and HGH was essential to bring home the boar, make it through the night, and survive. Look at the evidence on HGH – amino acids increase HGH, starvation increases HGH, and short-term stress increases HGH. That puts a picture in my head of a primitive human hunting an animal, short-term fight or flight instinct kicks in, he kills the animal, and then eats that animal protein high in amino acids. Then there are days where no food is around so the primitive human goes into starvation for a while. That’s just my theory though. Lets get down to business.
Anabolic processes tend toward "building up" organs and tissues . These processes produce growth and differentiation of cells and increase in body size, a process that involves synthesis of complex molecules . Examples of anabolic processes include the growth and mineralization of bone and increases in muscle mass. Endocrinologists have traditionally classified hormones as anabolic or catabolic, depending on which part of metabolism they stimulate. The classic anabolic hormones are the anabolic steroids , which stimulate protein synthesis, muscle growth, and insulin .  The balance between anabolism and catabolism is also regulated by circadian rhythms , with processes such as glucose metabolism fluctuating to match an animal's normal periods of activity throughout the day. 
The most commonly used AAS in medicine are testosterone and its various esters (but most commonly testosterone undecanoate , testosterone enanthate , testosterone cypionate , and testosterone propionate ),  nandrolone esters (most commonly nandrolone decanoate and nandrolone phenylpropionate ), stanozolol , and metandienone (methandrostenolone).  Others also available and used commonly but to a lesser extent include methyltestosterone , oxandrolone , mesterolone , and oxymetholone , as well as drostanolone propionate , metenolone (methylandrostenolone), and fluoxymesterone .  Dihydrotestosterone (DHT; androstanolone, stanolone) and its esters are also notable, although they are not widely used in medicine.  Boldenone undecylenate and trenbolone acetate are used in veterinary medicine .