where are b12 injections administered at Home - Safety Guide for Self-Administration Where to Inject Vitamin B12
Description
Even some meat eaters dont absorb it very well (4, Unlike other vitamins, the absorption of vitamin B12 depends on a protein produced in your stomach, called intrinsic factor

common reactions include transient pain, erythema, or pruritus at the administration site, along with mild diarrhea, headache, or nausea in a minority of recipients

R., et al

Not approved by the FDA or TGA.