Efficacy of different routes of vitamin B12 supplementation for the treatment of patients with vitamin B12 deficiency: A systematic review and network meta analysis Irish Journal of Medical Science (1971 ) What is B12 Injection Used for? ThinWorks B12 Injections vs. Sublingual MTHFR B12 Methyl Life Supplements Quick question why do people talk about B12 injections versus ingestible pills? I wish I injections. I do not have the cash for that little backstory. I've been eating vegan style for Vitamin B12 Deficiency? Heres the best way to treat it!, Many people take oral or sublingual tablets, but they may not always be effective especially if absorption is poor., The active injectable