AHK-Cu works with it
Though rare, serious allergic reactions and anaphylaxis can occur, particularly with parenteral thiamine
Efficacy and Safety of Mecobalamin on Peripheral Neuropathy PubMed / systematic review article: Concludes that mecobalamin (alone or combined) may improve clinical outcomes and nerve conduction in peripheral neuropathy
What the trial data shows
There are also certain drugs and health conditions that can increase the likelihood of developing a B12 deficiency such as: alcohol abuse, antacid use, smoking, celiac disease, other digestive concerns, pregnancy, a strict vegetarian or vegan diet, and even natural aging
Hydroxocobalamin has a long safety record, no meaningful overdose risk because excess is excreted in urine, and a very low rate of allergic reactions