Benefits of a Vitamin B12 Injection, Vitamin B12 injections are commonly used for people who are deficient, struggle to absorb B12 from tablets, or require a faster and more effective boost., Helps Vitamin B 12 intramuscular injections are also used therapeutically to help restore energy and combat various symptoms related to such deficiencies. Vitamin B 12 is essential to the development of healthy blood cells, nerve 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. B12 Shots & B12 Injections: The Good, Bad and Alternative!