Cyanocobalamin (Vit B12) Injection for Pets VetRxDirect B12 vitamin Store Intramuscular vs Subcutaneous Injections for vitamin B12 supplements. Types of Injections, Same Needle Different Depths IV, IM, SC, and ID look similar but act very differently inside the body. This visual shows where each injection goes, how deep it travels, Needle Injection Techniques Every Nurse Should Know! Whether you're prepping for your NCLEX or brushing up on your skills, here's a quick breakdown of the most common injection routes you'll encounter How to Administer an Intramuscular Injection at Home