Unnecessary vitamin B12 shots costing Ontario millions, study finds CBC News What Are B12 Injections? And Are They Safe? OmegaQuant Vitamin B12 injections deliver high doses of this essential vitamin directly into your bloodstream for better absorption than oral supplements to boost energy, support red blood cell production and maintain nerve function. A vitamin B12 injection is a shot that delivers B12 directly into your muscle, helping your body absorb it quickly (especially if your body struggles to absorb it from food or tablets)