doi: 10.1038/s41392-020-00315-3 141 LublinF
Cardiovascular risk evidence uses the 2.4 mg dose
In patients with serious bleeding events, conditions that increased the risk for bleeding were often present, or patients were often taking drugs that cause thrombocytopenia (other antiepileptic drugs) or affect platelet function or coagulation (e.g., aspirin, nonsteroidal anti-inflammatory drugs, selective serotonin reuptake inhibitors, or warfarin or other anticoagulant therapy)
But, theres a catch If you have ileitis (inflammation of the ileium), Crohns Disease affecting your stomach or small intestine, or have had a bowel resection, chances are that you might be deficient in B12 because you arent able to properly absorb it through your gut (SOURCE)
Use standard PPE: gloves, lab coat, eye protection
Again, Im not sure as to why certain people seem to respond better to B12 shots vs oral B12 supplements but its worth knowing