Testosterone can be administered parenterally , but it has more irregular prolonged absorption time and greater activity in muscle in enanthate , undecanoate , or cypionate ester form. These derivatives are hydrolyzed to release free testosterone at the site of injection; absorption rate (and thus injection schedule) varies among different esters, but medical injections are normally done anywhere between semi-weekly to once every 12 weeks. A more frequent schedule may be desirable in order to maintain a more constant level of hormone in the system.  Injectable steroids are typically administered into the muscle, not into the vein, to avoid sudden changes in the amount of the drug in the bloodstream. In addition, because estered testosterone is dissolved in oil, intravenous injection has the potential to cause a dangerous embolism (clot) in the bloodstream.
I know Arnold used since his teens and year round – thats why I mentioned my knowledge via his trainers. It still isn’t shit compared to what the guys use now, obviously. It was a tiny amount of steroid use compared to todays guys. Steroid use is a must for pros – I don’t think that is even an argument. It’s not about shortcuts, its about being able to obtain the size and shred – period. Without them there is only a certain level a competitor can go. I’ve never looked down on the 70’s era BB’s because they did it smartly and conservatively (again, relatively speaking).
Anabolic steroid use, versus steroid abuse, requires access to various steroids (to use the one that best fits the athlete in question), and regular blood work and monitoring from a physician. Because of these factors, steroid abuse can cause very damaging effects. Liver toxicity is a common problem. Suppression of natural hormone production in the body can be seriously effected by misuse of steroid regimens – this includes stunted growth in users and abusers who are not fully grown. Other problems include cardiovascular issues, cholesterol problems and increased aggressiveness.