How Can Vitamin B12 Shots Help Me Feel Refreshed Dr. Nasseri How Soon Do You Feel Less Tired After a B12 Injection? 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 B12 Injections Lucia Medical Aesthetics Main benefits of B12 injections 1) Increased energy & reduced fatigue B12 helps convert food into usable energy Deficiency often causes tiredness, weakness, and low stamina 2) Healthy red blood cells Prevents