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.
The brand name Winstrol refers to a steroid made of the compound Stanozolol. It is used by the muscle gaining community in muscle mass and strength gain. Performance athletes and bodybuilders widely use it. Due to its chemical makeup, Winstrol is a very mild steroid. It being mild explains why it is loved by athletes engaging in activities that require a lot of strength. Because of its low potency, it is considered to be very dangerous to the human body. It is considered so because; Winstrol contains a high dosage of androgens which is less potent and a low dosage of anabolics. For this reason, the medical world considers it as a very dangerous steroid, contrary to the popular belief by its users that it is safe.