You don't pin the muscle, 27g x 1/2 is for subcutaneous injections. I first heard about it here, so I checked with my doctor and she said to go for it. I'll keep an eye on my bloodwork, but so far it's agame changerIsn't half inch too small?? I swear you'd need to be in contest shape for this to pin the muscle. I usually use 1 inch but 5/8 works too. I might try the 27g 5/8 or 30g 5/8