What size needle is used for testosterone injections?

I use a 23 guage 1 inch long needle for injections into my thighs. About 1 in 4 or 5 times that I do an injection I get a little bit of testosterone leaking back out of the puncture. I have used 22 guage 1.5 inch long needles but they seemed a bit to large in diameter and length. I am going to ask for 23 guage 1.25 inch long the next time that I get a refill of needles, this seems like it should be the perfect size for my needs. By the way, I am a big guy and if I were smaller, I think the 1 inch in length would be fine. When I first started my shots, I was getting a 1ml. shot once per month. My levels were still to low so I went to 1ml. every 2 weeks. This got my T levels where they should be but I broke out with acne on my chest and back. After some research I started doing 1/2ml. every week and in about 6 weeks the acne had went away. My T levels spiking after a 1ml. shot was the cause of the acne and is not a problem with the 1/2ml. shots. Everyone is different but don't be afraid to customize your treatment for your needs.