So your taking a injection only once a month? The half life is around 12 days I think. Your going to feel ok for a week (not great) and go back down to natural testosterone levels with in about two weeks. To me, injections should be done weekly. Just seems it's too little and too far in between injections. You might even feel worse in weeks 3 and 4, because your natural testosterone might be shutoff during that time (not sure), so you would have very little testosterone during that time.