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.
Metabolic effects occurring during anabolic steroid therapy in immobilized patients or those with metastatic breast disease include osteolytic-induced hypercalcemia .
Anabolic steroids effect electrolyte balance, nitrogen retention, and urinary calcium excretion. Edema, with and without congestive heart failure, has occurred during anabolic steroid therapy.
The androgenic activity of anabolic steroids may decrease levels of thyroxin-binding globulin, resulting in decreased total T4 serum levels and increased resin uptake of T3 and T4. Free thyroid hormone levels remain unchanged, however, and there is no clinical evidence of thyroid dysfunction.
Significant increases in low density lipoproteins (LDL) and decreases in high density lipoproteins (HDL) have occurred. [ Ref ]