Sorry for answering like a jerk - it was late and I was tired. Most people don't want to do subq (typically in the stomach) testosterone because IM (intramuscular) test has always been the way its been done. However, it is very effective done sub q, so much so in fact, that females transitioning to males do so, and do so successfully - that's how freakin' effective it is. Testosterone is also actually metabolized in your fat cells, so doing it in the stomach makes sense too. Additionally, if someone is on it for life (which is usually the case in
actual TRT situations) , it is much better to poke a tiny hole in your stomach fat than in your glutes, quad or shoulder muscles. IM shots can hurt and bleed more too. Sub Q shots are more like a sharp pinch - the needles are way smaller. The only real drawback in my opinion is that it takes longer to draw and inject, not that anyone should be in a hurry to administer their shot anyway.
I have researched this quite a bit as I've been on TRT for about 3 years (48 year old male and I actually did have very low T to start). I started IM for about a year and then switched to Sub Q after learning more about it. We had to drop the dose after going to Sub Q as my numbers were off the chart - they were Vitor territory !!!
Hope this is informative.
Here are some links:
https://www.researchgate.net/public...stration_of_testosterone_A_pilot_study_report
https://www.healio.com/endocrinology/hormone-therapy/news/online/{83839fda-5dd3-482f-bc4e-ea9170c799ac}/subcutaneous-testosterone-offers-alternative-to-intramuscular-injections-in-transgender-men
https://www.ncbi.nlm.nih.gov/pubmed/28379417
https://www.t-nation.com/pharma/get-20-better-results-from-testosterone