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Needle Size for IM vs SC

Can I use 29g 1/2 inch needle for IM injection in delts or glutes fat pad area? I bought these for SC but going with IM admin. I also have 27g 1/2 inch. Is there much of a difference. I am not so much worried about how long it takes to draw as only injecting 2x week. Any recommendations are appreciated.

I use 28g 1/2 IM thighs or delts without issue. You’re good to go!

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Depends on how much fat you have. I think I have about 1/4-3/8” fat in my delts so it’s pretty much SubQ for me. My thighs have almost no fat, so it’s for sure IM.

I use 1/2” 30g for shallow IM delt injections. No issues.

No. Too short. Too thin. 1-1.5 inch depending on muscle and body fat.

You would recommend a 1.5 inch needle for delts? Are you shooting for bone marrow?

What’s your bf percentage? I’ve been in total joint replacement surgeries with literal obese people who could do IM with a 1/2 inch needle in the lateral deltoid. It’s basically skin over muscle for those that are even remotely in shape.

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I’m only about 20-25%. Maybe I’m overestimating how much fat I have there. When I pinch my skin, I can grab a solid 3/4 of an inch of skin and fat.

Proximal humerus surgery.


For comparison reasons here’s the fat layer of the thigh.


For some reason watching surgery doesn’t bother me. As long as it doesn’t involve eyes

Great pics!