How to Inject Vitamin B12 medicalweightlosscentersofamerica.com Insulin injection sites: abdomen (fastest; avoid 5 cm around navel), thighs (slower), upper arms (moderate), buttocks (slowest); rotate sites to prevent lipodystrophy. Disclaimer For educational purposes only. Not medical advice. Administer insulin Subcutaneous (SC) and Intramuscular (IM) Injections Must Knows for Subcutaneous administration: Pinch skin with non dominant hand and hold syringe with dominant hand Always inject: 2 inches away from umbilicus (for abdomen) 3 inches Common IM Injection Sites Deltoid (Upper Arm) Location: About 23 finger widths below the acromion process (shoulder bone). Best for: Vaccines and small volume injections (1 mL). Notes: Easy to access but limited