There may be instances where certain conditions, such as poor nutrition, intestinal issues, infections, and cancer, may lead to B12 deficiency
Older people usually produce less stomach acid and therefore less intrinsic factor, increasing their risk for deficiency
Injection Site Reactions: With subcutaneous administration, mild redness, swelling, or irritation at the injection site may occur
fluid build-up in or around the lungs - pain when you breathe, feeling short of breath while lying down, wheezing, gasping for breath, cough with foamy mucus, cold and clammy skin, anxiety, rapid heartbeats
The rate of infusion is set to give the dose over 30 minutes to 1 hour
For B12 injections, needles with lengths between 1 to 1.5 inches are often recommended