lingering pain after b12 injection in thigh Best Vitamin Sites How to Administer an Intramuscular
Description
Your deficiency is moderate to severe, causing significant symptoms like anemia or neurological problems
According to the NIH Office of Dietary Supplements, vitamin B12 is available as cyanocobalamin and hydroxocobalamin, which are typically administered parenterally by intramuscular injection to bypass gastrointestinal absorption barriers

They give you a single chart and pretend it works for everyone

Vitamin injections are effective because it does not have to go through the GI tract
But the implications of this in dogs is not known