When Taking Vitamin B12 orally place it under the tongue. It will be fully absorbed into the bloodstream. If you swallow it the digestive system will interfere with the amount u absorb Vitamin B12 Injections vs. Oral Supplements: Which Is Better? Vital Force IV Therapy B12 deficiency doesn't always look obvious. It usually shows up as things people brush off low energy mental fog feeling off but not sure why The problem is, oral Oral vs. Intramuscular Vitamin B12 in Vitamin B12 Deficiency The Blood Project Oral vs. Intramuscular Vitamin B12 in Vitamin B12 Deficiency The Blood Project