adverse reaction to b12 injection Vitamin B12: Overdose and Side Effects Can Vitamin b12 Injections Cause
Description
Several important factors warrant consideration: Concurrent medications and supplements frequently contribute to gastrointestinal symptoms

Yes, its very safe

Concurrent medications (metformin, PPIs, antibiotics) and underlying gastrointestinal conditions may cause diarrhoea coinciding with B12 supplementation

If its too warm, the protein in the medication can break down
