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.
Regarding the proviron, I mainly added it to cut some water gained on the test enanthate (I eat 100% clean but carbs are Not my friends, unfortunately). Also I wanted to improve my Sex life with girlfriend. I am really happy with the decision to Add Dragon Pharma proviron to my Cycle: vascularity improved a lot, morning wood back again, lot more Libido and I was able to cut some water, much more satisfied when looking into the mirror every morning.
Side notice: used Pharma proviron from bayer before in the past a lot, Dragon pharma are as good as them!