oral b12 vs injection Vitamin Intramuscular Injections Versus Supplements: A Budget Impact Analysis B12 Injection vs. Oral Supplements:

(PubMed) Desmond MA, Sobiecki JG, Jaworski M, et al

The short answer

If a patient without a diagnosed vitamin B12 deficiency is receiving the vitamin through regular injections to experience the multitude of benefits, the frequency of these injections can vary quite a bit depending on the reason they are getting the injections (weight loss treatments will likely have a higher frequency of vitamin injections than other treatments) and this timeline will be established by the patient and the specialist providing the injections to ensure that the treatment is both as safe and as effective as possible

It is particularly common among older demographics, where skin becomes less effective at producing Vitamin D, or among people with darker complexions

A subsequent randomized controlled trial reaffirmed this comparable efficacy in adults