What is an acceptable oral vitamin B12 (cobalamin) supplement alternative to intramuscular injections for a patient with severely low vitamin B12 levels, particularly those with malabsorption or pernicious anemia? Vitamin B12 Oral vs Injection Recently I have been asked a lot for VitaminB12 injections. I initially decided not to offer vitamin B12 injections as some literature showed that the efficacy of oral vitamin B12 was the B12 Injections vs. Oral Supplements: Which Is Better? Vitamin B12 is essential for energy production, nervous system function, and red blood cell formation. However, oral B12 supplementation doesn't work well for everyoneabsorption can be limited by digestive issues, certain medications,