Changing brands of vitamin B12, forms of B12 (cyanocobalamin vs hydroxocobalamin), or switching from injections to tablets can be a solution in those (rare) cases
If you're committed to longer protocols, buying larger makes economic sense
Eating B12-rich foods like meat, eggs, and dairy or taking supplements daily can also help raise levels over time
[PMID: 32566305] PubMed record related to this compound for laboratory literature review
Smoday I.M., Petrovic I., Kalogjera L., Vranes H., Zizek H., Krezic I., Gojkovic S., Skorak I., Hriberski K., Brizic I., et al
You Have to Try It But I cant give up bread I hear this all the time