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.
Clenbuterol is not an anabolic steroid, it does not express or exhibit any of the known side effects that are associated with anabolic steroid use. Instead, clenbuterol expresses side effects that are common to all drugs and compounds in the stimulant class. Perhaps the most unique of clenbuterol side effects is the commonly reported side effect of muscle cramping. The cause of this is through Clenbuterol’s depletion of taurine in the body. Taurine, alongside magnesium, potassium, and sodium, play very crucial roles in the regulation of bioelectrical nerve impulses and signals that govern the contraction and relaxation of all muscle tissue types. When taurine is depleted, involuntary and often intense and painful muscle contractions that lead to cramps can result. Supplementation with taurine at – 5 grams per day can mitigate this side effect.