What's your body type..? Meso and ecto should be fine, endomorphs may need 1 1/2" pins cause they tend to be thicker with more bf...I use 1" pins for all my injections..As long as you're not a visibly overweight person then 1" should be gtg. You don't need to go THAT deep in the muscle, as long as the oil goes into the muscle you're fine and going an inch deep should pretty much always accomplish that!