When I took testosterone, which I did for three years, I got a shot in the rump.
The doctor allowed me to self medicate to some degree by saying I could come in every three to four weeks. Wonderful stuff for me. YMMV.
When I first began getting shots there was little change so the doctor had me come in for an additional shot at a higher dosage. The combination made my scrotum, and it's contents, shrink to nothing. Absolutely freaked me out.
Really sorry my current doctor doesn't think I need it.