allergy to b12 injection Vitamin Injections (Cyanocobalamin Injections) — Mountainside Medical Vitamin B12 Side Effects

(Green R, et al., Nature Reviews Disease Primers, 2017 PubMed: 28660890 ) Because B12 is water-soluble, excess amounts that the body cannot use are excreted in urine rather than stored

Here are some recommendations for B12 dosages depending on your circumstances

doi: 10.1038/s41467-020-20790-0 [DOI] [PMC free article] [PubMed] [Google Scholar] 11

Unless the argument is that those people can access their B12 stores and you cannot, but I don't think we can assume that

If you have increased organ fat or visceral obesity, you run a higher risk of diabetes, high blood lipids, and insulin resistance

But those mechanisms require substrate (stored fat being mobilized through caloric deficit) to act upon