Pharmaceuticals, 18(2), 185.
On top of that, we know that only a small percentage of vitamin B12 taken orally is actually absorbed
Modulatory Effects of BPC 157 on Vasomotor Tone and the Activation of Src-Caveolin-1-Endothelial Nitric Oxide Synthase Pathway, Hsieh MJ, Lee CH, Chueh HY, Chang GJ, Huang HY, Lin Y, Pang JS, Scientific Reports, 2020 Oct 13;10(1):17078.
Your body cant make it on its own you get it from food (mainly animal products) or supplements
Many adults and children with B12 deficiency report experiencing paresthesia, a burning or pinprick sensation in certain parts of the body, such as the hands and feet