How to Self Inject Vitamin B12 at Home The Sanctuary Wellness Institute Instruction Guide for Intramuscular (IM) Self injection of B12 Methylcobalamin 1mg 5mg Feeling low on energy? Your body might be telling you something. Vitamin B12 is essential for energy, mood, and brain function. If you're experiencing fatigue, weakness, or brain fog, a B12 injection How to self inject intramuscular vitamin B12 Overview Guy's and St Thomas' NHS Foundation Trust