Vitamin B12 Deficiency: Signs & Symptoms Vitamin B12 is essential for nerve health, red blood cell formation, and brain function. When B12 levels are low, symptoms often develop slowly and silently, B12 Injections: Who Should Get Them and How Long Do They Last? What Happens If You Inject B12 Wrong: 6 Red Flags Why aren't my b12 shots working : r B12_Deficiency If I took vitamin B12 injections and folic acid along with magnesium, a B complex, and carnitine, but there was no improvement and my condition actually worsened with increased anxiety, does this mean