When first administering steroids, a man will have an increase in sexual function. This unfortunately is only temporary as your body becomes used to the steroid in its system. With prolonged use of a steroid, eventually, the man will feel less sexual desire, and will be less capable of maintaining an erection. Luckily, this is only temporary as well and can even be totally prevented with the use of substance such as Gonakor and HCG. Also when the steroid use is discontinued, the body’s natural level of testosterone (like the immune system) will certainly be suppressed.
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.
Water based or Aqueous testosterone suspension can peak in the blood stream within minutes of being injected and is metabolized very fast. Because Testosterone Suspension remains in the body for a short time, it has to be injected very frequently. In most cases Testosterone Suspension has to be administered daily or few times a day in order to maintain a stable blood testosterone level. If Testosterone Suspension is your preferred choice you can rotate injection spots each time rather than injecting the same location each day. This form of testosterone is not highly recommended and is often used by very experienced and extreme athletes, body builders and power-lifters. This testosterone form give the best strength results and a high aggressiveness. It also exist a testosterone with no ester and oil based called TNE (Testosterone No Ester).