TweetThe length needed depends on where the shot is and what your body fat percentage is. A lean person can hit the thigh muscle with a 1/16th in needle - though it would barely penetrate (which is why they do not make such a thing).

I use a 27g, 1/2in when I do my standard TRT shots - the oil moves through easily. When I do a larger amount (such as during a cut or blast), I use a 27g, 1in. For my Test in Water shots, I use a 23g, 1in.