When food sits in your stomach for extended periods, the normal B12 absorption cascade faces disruption
But calling your pharmacy to confirm is always the safe choice
[1] Most often for at-home therapy, it will be IM injections
Nevertheless, use of metformin may decrease vitamin B 12 status: a meta-analysis of four short-term intervention trials (up to 4 months duration) in patients with type 2 diabetes found that metformin use decreased serum cobalamin concentrations by 57 pmol/L, which could have clinical implications if such patients have suboptimal vitamin B 12 status (146)
[4] Based on animal research, it is thought that the increased methylmalonyl-CoA hydrolyzes to form methylmalonate (methylmalonic acid), a neurotoxic dicarboxylic acid, causing neurological deterioration
Methylcobalamin has some metabolic and therapeutic in applications not shared by the other forms of vitamin B12