1 Energy You Can Feel Vitamin B12 helps your body turn food into usable energy. Low levels can leave you feeling constantly drained, no matter how much sleep you get. 2 Brain Vitamin B 12 Injection, 5,000 mcg mL, 100 ml IV therapy can be used to rapidly replenish B12 levels. , Increases Energy, Improves Immune Function, Regulates Mood, Why B12 Injection over B12 Supplement? Great Question!! , An injection of B12 Injections vs Oral Supplements: Which are more effective? Volonte Vitamin B12 shots: Uses, benefits, and side effects