B12 Shots: Benefits, Uses, Safety, Cost & How They Work Vitamin B12 Intramuscular Injection Instruction Videos YouTube Taking Vitamin B12? Read this first. While B12 is often hailed as a safe energy and brain booster, many real users are reporting unexpected side effects including anxiety, insomnia, B12 Shot for a B12 Deficiency: Is It Worth It? How to Self Administer Subcutaneous & Intramuscular Injections B12 Shots: Vitamin B12 Injections Benefits, Uses, Risks Dr. Axe