B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics What are Vitamin B12 injections Vitamin B12 injections are used to quickly raise your B12 levels when they're low or when your body can't absorb it properly from food or tablets. What It might not be your lifestyle it could be a B12 deficiency. B12 is essential for energy, mood, and overall wellness and when levels are low, your body feels it. Our How Often Can You Get a B12 Shot for Maximum Health?