OK, so I have an interesting data point to pass along. Disclaimer: As stated above, I tend to micromanage TRT and closely watch my subjective and objective response to it.I tried the abdomen and never liked it. The love handles though are very easy for me, I feel like I could just inject there and skip the VG and shoulders. But it's nice having six locations so that's why I do all six.
For years, I have done daily hCG and recently have added daily small test/nandrolone injections. I tend to use the subcutaneous fat in the abdomen. Once in a while, I go out to the "love handle" area (I call it "flank" area). Based on @Vince's enthusiasm for it, I decided to do a flank injection for both hCG and test/nandrolone the other day. The results were really bad.
I felt "off" and had a low grade headache all day. I also noticed a flare of acne (body and face) that crept up late in the day. Since I started the low dose daily injections, acne has been receding, but this day, I had several spots pop up.
I know - it sounds almost ludicrous that one flank injection could do this, so I checked my spreadsheet (You heard it right: I have been keeping a spreadsheet for about a year, tracking things like TRT modality/dose/location/time BP, headaches, anxiety, mood, etc. so that I can learn from successes and failures and track trends), and I found other entries in which I stated I used the flank area and noticed increased acne and headaches.
I suspect that there is a real phenomenon here. Not sure how to explain it - the fat milieu could affect absorption or metabolites? Maybe the location influences aromatization?
Do what you want with this tiny experiment.