When we perform testosterone injections we do not arbitrarily stick a needle into the muscle; there are specific points within each muscle that you want to use. Youve probably seen movies or . shows where some guy is supplementing with anabolic steroids and it shows him arbitrarily sticking a needle right into the meat of his butt and then shows him on the field as an animal; in real life that wouldnt happen as he would be temporarily paralyzed. The sciatic nerve runs through our glutes, often the area many movies portray the injection and if you hit the never youre not going to be moving for some time. Each area, each muscle has a spot that may be used and when we know the spots the process is very simple; in reality its no different than eating food its just most dont know how to do it. For example, you wouldnt take a hamburger and try to jam it into your eyeball to eat it, of course not, you know better and testosterone injections are no different.
Adverse effects of testosterone supplementation may include increased cardiovascular events (including strokes and heart attacks ) and deaths based on three peer-reviewed studies involving men taking testosterone replacement.  In addition, an increase of 30% in deaths and heart attacks in older men has been reported.  Due to an increased incidence of adverse cardiovascular events compared to a placebo group , a Testosterone in Older Men with Mobility Limitations (TOM) trial (a National Institute of Aging randomized trial) was halted early by the Data Safety and Monitoring Committee .  On January 31, 2014, reports of strokes , heart attacks , and deaths in men taking FDA-approved testosterone-replacement led the FDA to announce that it would be investigating the issue.  Later, in September 2014, the FDA announced, as a result of the "potential for adverse cardiovascular outcomes", a review of the appropriateness and safety of Testosterone Replacement Therapy (TRT).    The FDA now requires warnings in the drug labeling of all approved testosterone products regarding deep vein thrombosis and pulmonary embolism . 
Fluid and electrolyte disturbances: Retention of sodium, chloride, water, potassium, calcium, and inorganic phosphates.
Gastrointestinal: Nausea, cholestatic jaundice, alterations in liver function tests, rarely hepatocellular neoplasms and peliosis hepatis (see WARNINGS ).
Hematologic: Suppression of clotting factors II, V, VII, and X, bleeding in patients on concomitant anticoagulant therapy, and polycythemia.
Nervous system: Increased or decreased libido, headache, anxiety, depression, and generalized paresthesia.
Allergic: Hypersensitivity, including skin manifestations and anaphylactoid reactions.
Vascular Disorders: venous thromboembolism
Miscellaneous: Inflammation and pain at the site of intramuscular injection.