Water soluble vitamins, like B12, can be tolerated at higher doses without adverse effects upon the body, and the National Academy of Medicine has not established an upper limit of Vitamin B12 intake
Here are the specifics for needle size selection for IM injections: Needle Gauge : 22-25 Gauge : The gauge of the needle refers to its thickness
The influence of thyroid function on the coagulation system and its clinical consequences
Nayana Shetty, MBBS, MD Health Risks Associated with High B12 In some cases, high vitamin B12 levels symptoms can include unusual symptoms like anxiety or a rapid heartbeat, which are more likely associated with the underlying condition, not the elevated B12 levels themselves
However, it contains no bacteriostatic agents