Sorry not to have responded earlier Tammi-- I inject manually and was told by SS to go in at an angle, since I don't have that much fat to inject into-- otherwide I'd be going in too deep and injecting into muscle.However, if I go in too shallow (too much of an angle) the medication ends up sitting too close to the surface of the skin and I get more of a reaction. I do remember something about going in at 90 degrees if you you can pinch an inch of fat. I don't use AJ because I found my site reactions to be more managable without it-- I think that with that one you always go in at a 90 degree angle. There you of course adjust the depth on the nose of the thing rather than manipulating the angle so much. Bottom line-- I get site reactions no matter what; it's just a question of the degree. Who knew all those years ago-- I should have gone to nursing school so I can at least inject myself with confidence!